BS350 Conversion Factors and Tables

BS 350 : Part 1 : 1974 UDC 61 1 .i 68,3 : 13.081 CONFIRMED OCTOBER 1983

e Conversion factors and tables

I

Part I. Basis of tables. Conversion factors

i. 1

British Standards Institution COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

This British Standard, having been approved by Technical Coniinittec M/1?7 Quantitics units litid symbols, was pliblishctl under the authority of the Executive Board on 25 March 1974.

0 British Standards Institution, 1974

First published June 1930 First revision July 1944 Second revision of Part 1 February 1959 Third revision of Part 1 March 1974

ISBN: O 580 08471 X

Copyright Users of British Standards are reminded that copyright subsists in all BSI publications. bio part of this publication ;niay be reproduced in any form without the prior permission in writing of BSI. This does not prcclude the free use, in the course ol implementing the standard, of necessary details such as symbols and she. type or grade designations. Enquiries should hc addressed to the BSI Secretariat.

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The following BSI reference relates to the work on this standard : Committee reference M/127

Co-operating organizations This British Standard was prepared under the supervision of Technical Committee M/127, Quantities units and symbols. consisting of representatives from the following Government departments and professional and industrial oyganizations: British Steel Industry Chemical Society Department of Trade and Industry Department of Trade and Industry (National Physical

Electricity Council, the Central Electricity Generating Board,

Institute of Trading Standards Administration Institution of Chemical Engineers Institution of Electrical Engineers Institution of Gas Engineers Institution of Mechanical Engineers Institution of Structural Engineers Metrication Board

Royal Aeronautical Society

Society of Chemical industry

Labora tory)

and the Area Boards in England and Wales Faraday Society Post office Institute of Heating and Ventilating Engineers Institute of Physics Royal Society Institute of Printing

COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

BS 350 : Part I ; March 1974 UDC 51 1.1 68.3 : 53.081

Conversion factors and tables

Part i. Basis of tables. Conversion factors

CONFIRMED OCTOBER 1983

Amendments issued since publication

Amd. No. Date of issue Text affected

4153 July 1983 Incorporated in this standard

British Standards Institution 2 Park Street . London W1 A 28s Telephone O1 -629 9000 Telex 266933


BSI BS*350: PART*L

BS 350 : Part 1 : 1974

Contents Page

Co-operating organizations Inside front cover Acknowledgements 2 Foreword 3

Basis of tables. Conversion factors

Subject table(s) Associated

1. Number la, lb 2. Length 2 3. Area 3a, 3b 4. Volume and capacity 4a, 4b, 4c, 4d 5. Modulus of section, first

moment of area (see 4a) 6. Second moment of area, or

geometrical moment of inertia 6 7. Plane angle 7 8. Solid angle - 9. Time -

10. Linear velocity (speed) 10 11. Angular velocity 11 12. Frequency (see 11) 13. Acceleration 13 14. Mass 14a, 14b, 14c 15. Mass per unit length 15 16. Mass per unit area 16 17. S-c surface, or area per unit mass 17 18. Area per unit capacity 18 19. Density 19 20. Concentration 20 21. Specific volume 21 22. Mass rate of flow 22 23. Volume rate of flow 23 24. Traffic factors 24a) 246 25. Moment of inertia 25 26. Momentum (hear) - 27. Angular momentum - 28. Force 28 29. Weight (see 14a, 14b, 14c and 28)

4 5 7 9

15

15 16 17 17 17 19 19 20 20 25 27 30 32 32 34 36 38 38 40 42 42 42 43 45

74 S Lb24bbî OLLbL2û O W

Page 30, Moment of force, or torque 30 46

32. Pressure 32a, 326, 32c 48 33. Stress (see 32a, 32b, 32c) 54

35. Viscosity, kinematic 35 56 36. Energy (work, heat, etc,) 36a, 36b 58 37. Power 37 62 38. Temperature, including temperature

difference or interval 38 64 39, Specific energy 39 65 40. Heat content, volume basis 4Oa, 4ûb, 40c 67 41, Speciñc heat capacity 41 70 42. Speciñc entropy (see 41) 72 43. Heat capacity, volume basis 43 72 44. Heat flux density 44 73 45. Thermal conductance 45 74 46. Thermal conductivity 46 75 47. Thermal resistivity 47 76 48. Heat release rate 48 77 49. Thermal diffusivity (see 35) 77

31, Force per unit length - 48

34. Viscosity, dynamic 34 54

Appendices A. Commentary on imperial and metric

78 B. References B.l Detailed conversion tables 81

B.2 General information 83 B.3 Some other British

systems of measurement and units

Standards containing conversion information 83

Figure 1. Fuel consumption 41

Indexes 1. Alphabetical list of symbols for units

and prefixes 84 2. General index 88

Acknowledgements The Committee responsible for this revision acknowledges with thanks the assistance provided by Mr. A. C. Hutchinson, C. Eng., in the formative stages of the planning and drafting, and later by Mrs. Pamela Anderton of the National Physical Laboratory who gave expert advice and personally checked the tables of factors.

2


BS 350 : Part 1 : 1974 Foreword This standard deals withinterconversion from one unit of measurement to another for a number of quantities which are in general use in engineering, industry and trade. The subjects covered are, broadly, metrology, mechanics and heat; the standard does not deal with purely electrical units. BS 350 was first published in 1930, and was revised in 1944 and again in 1959. It was then that the standard

was split into two parts, Part 1 dealing with the basis of tables and conversionfuctors, and Part 2, which first appeared in 1962, giving detailed conversion tubles for the more frequently used conversions. From those tables in Part 2 conversions could be read off directly or assessed by interpolation, and the onus of i t u j m d l u

multiplication by a six figure factor was removed. In I967 a Supplement (PD 6203) was issued to Part 2, giving additionat detailed tables for SI conversions. BS 350: Part 2 was withdrawn in 1981 since many of the tables .ilfrfificf/

calculators was considered to have made such tables, which often required interpolation, obsolete. PD 6203 is, however, still valid and has been retained.

This, then, is a revision (confirmed on the incorporation of Amendment No. i in 1983) of BS 350 : Part 1 : 1959 and provides a comprehensive list of conversion factors and notes on their use. T h e units i n about fifty quantities of measurement are given, together with such definitions, and information on the derivation of conversion factors, as are considered necessary for the purpose.

The experience gained with the earlier editions has been a reliable guide to the choice of quantities to be treated in this revision. Only information now considered obsolete has been discarded, and the quantities dealt with liave remained substantially unehaiiged. There have, however, been considerable additions made to the units, and consequently to the conversion factors, and the standard has been fundamentally re- arranged for the reason which follows.

In this edition, while interconversion factors between all the important units treated are given, the standpoint i ~ . I t i ~ t ~ ~ n s r c t l

from which the various units and conversion factors are discussed is the SI. This marks a n important departure ii-Oni the earlier editions which originally argued from the imperial system and later perforce adopted a mixed imperial-metric standpoint. Imperial units are being progressively discarded and their retention as the standpoint in this standard would have acted as a brake to the progress of metrication. Furthermore, the SI, under the custody of the General Conference of Weights and Measures, forms the precise and natural basis for conversion information on units, and on'crs firm prospects ofan internationat harmonization in unit practice, after which conversion factors wili no longerbe required.

stated accuracy. The other important but extraneous information in it is there to help the general user when he is faced with the need to make conversions. BS 350 does not purport to define quantities or units, or to standardize the letter symbok or abbreviations used for units. These matters are dealt with elsewhere, but their mention is necessary here and has been made up-to-date with the latest international

Where factors are given in bold print it is to show that they are exact; in general, factors have been rounded to include six signiíicant figures, thus permitting accuracies satisfactory for most practical purposes. The computation of each factor has as far as possible been made from first principles, using eight or more signiñcant figures to minimize the possibilities of errors in rounding. By comparison with previous editions (including BS 350 : Part 2) deviations by one digit in the last signifìcant figure of factors involving the UK gallon may sometimes be noticed. These have arisen because the computation in the previous editions was based on I üKga l=4 .546 09 dm3. Since November 1976 the definition o f t h e gallon in the Weights and Measures . A W I ' ~ I ~ A ~ ~ /

Act 1963 has been 4.546 (19 dm3. Before that date the definition in theweights and Measures Act 1963 was such that the gallon could be caIculated to be 4.546 O91 879 dm3 to ten significant figures and, on advice from the NationaI Physical Laboratory, a more accurate factor was used as a basis for the computation in the present edition. The return, in November 1976, by precise definition to what had earlier been used as a n approximation for the value of the galion (Le. 4.546 O9 dm3) clearly implies changes, in some cases, in the final figure of factors involving the UK gallon and in particular, the reversal of the changes as described that occurred between the present and the previous editions of the standard. Table 23 has however now been corrected in this respect. The six significant figures given for conversion factors involving the 15 "C calorie ace not warranted by the accuracy of definition of that particular unit, but have been retained for the sake of consistently in the layout of the tables.

Six-figure factors are unnecessarily precise for many practical purposes, and will be rounded to fewer significant figures as appropriate. The Department of Trade and Industry has asked users of these tables to be reminded that conversions for trade purposes should be based on the statutory deñnitions of units in the Weights and Measures Act, 1963. Section 24 of that Act makes it an offenoe to give short weight or measure (or to overcharge for the goods supplied if they are offered at the stated price per unit weight or measure). The conversion factors should therefore always be chosen so that the rounding is in the customers' favour, regard being paid to any statutory requirement (such as Marking of Goods Regulations) there may be in this respect.

Jirii ifi.i.+

included in it had become inconsistent with the International System of Units (SI) and the increasing use of pocket Jirlt iYh3

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Jiili i W 3

The standardization function of this standard Iies in the provision of conversion factors reliable to a f r u i r l c i i i l t w Jirli iW.3

I \ d t h v i and national decisions, dill1 I W

Jirli iY33

3


BS 350 : Part I : 1974

British Standard

Conversion factors and tables Part 1. Basis of tables. Conversion factors

i . Number

1.1 The following preíkes, with significance, iianie, and symbol as shown below, are used to denote decimal multiples or submultiples of (metric) units. These prefixes developed in conjunction with the metric system, and are now authorized as ' SI prefixes '.

Table la . Prefixes denoting decimal multiples or submultiples To indicate multiples

To indicate submultiples

x 10-1 x 10-2

x 10-6

x 10-12

x 10-18

x 10-3

x 10-9

x 10-15

deci centi milli micro nano pico femto

~ atto

d

m P n P f a

C

1.2 Regarding the meaning of million, biilion, etc. the convention shown in Table lb, accords with the decision of the 9th General Conference of Weights and Measures, Paris 1948, and is in use in European countries including the United Kingdom.

Table ib. Meaning of million, billion, trillion, etc.

Tenn

million biiiion t a o n quadrillion

Significance

thousand x thousand million x million million x billion million x triilion

Corresponding decimal factor

106 1012 1018 1024

A different convention is in use in the United States of America, where ' miliion signiíies a thousand times a thousand (109, ' billion ' signifies a thousand times a million (log), ' trillion ' signifies a million times a million (1012), and ' quadrillion ' signifies a million times a US billion (1015).

In view of the differences between European and USA practice, ambiguities can easily arise with the words ' billion ', ' trillion ' and ' quadrillion ', therefore their use should be avoided.

4


e

O

BS 350 : Part I : 1974 Length

2. Length 2.1 The SI unit of length is the metre (symbol m). It is one of the base units of the S1 and is now defined in terms of a specified number of wavelengths of a particular atomic radiation, as given in BS 3763, NOTE. The titles of BS 3763 and all other British Standards referred to in this text are listed on the inside back cover. 2.2 Multiples and submultiples of the metre are formed by using any of the SI prefixes given at 1.1; kilometre (km), decimetre (dm), centimetre (cm), miliimetre (mm) and micrometre (pm) are common examples. An alternative term for the micrometre, abrogated by the CGPM but st i l l in common use, is ‘ micron ’. The symbol p, associated in the past with the micron, is incorrect; pm should be used. 2.3 Some units of length having associations with the metric system but not forming part of the SI are:

i angström (A) = 10-lOm Refer to note 1 international nautical mile (n mile) = 1852 m 1 astronomical unit (AU) = 1.496 x 1011 m 1 1 parsec (pc) = 3.0857 x 1016m 2 1 light year (1 .y.) = 9.4605 x 1015 m 3

2.4 The definitive UK (or imperial) and US unit of length is the yard, legally deíined (since 1959 in the USA and since 1963 in the UK) as follows:

2.5 The connection between multiples and submultiples of the yard is indicated in the foliowing traditional table of named UK and US units of length, defined (for the UK) in the Weights and Measures Act, 1963.

Refer to note 4

1 yard = 0,9144 m

(1 in = 0.0254 m) = 0.3048m)

(1 yd = 0.9144 m) 1 foot (ft) = 12 inches (in) (1 f t

1 chain == 22 yards (yd) (1 chain = 20.1168 m) 5 1 yard (yd)= 3 feet (ft)

I furlong = 10 chains (1 furlong = 201.168 m) 1 mile = 8 furlongs (1 mile = 1609.344 m) 6

1 micro-inch (pin) Refer to note 1 thou = 10-3 in = 25.4 pm = 25.4 x 10-6 m 7 1 mil = 10-3 in = 25.4 pm = 25.4 x 10-6 m 8 1 point - - in (approx) = 0.351 mm (approx) 9 1 iron - Ain = 0.529 167 itîm 10 1 line - 1 - .in = 0.635 1111i11 11 1 line or ligne - - &in = 2.116 671111i11 12

2.6 Some less usual, or more specialized, UIC and US named units of length are: = 10-6 in = 0.0254 pm = 25.4 x 10-9 m

-

1 em - - 1 .in = 4.233 33 mm 13 1 hand = 4 in = 10.16 cm 14

= 0,201 168 m 1 link 1 US survey foot _ - O.!iDA9B ft e= 38.87 18 = 0.304 801 m 1 fafhom y = 6f t = 1.8288 m 1 rod, pole, or perch = 5+ yd = 5.0292 m 15 1 engineer’s chain = looft = 30.48 m 1 cable-length - - 16 1 UK nautical mile = 6080 ft = 1853.18m 17 1 telegraph nautical mile = 6087 ft

- - chain = 0.66 ft -

= 1855.32 m Notes on section 2

I. Approximalely the mean distance between the Sun and the Earth. 2. The distance at which 1 AU subtends an angle of 1 second (1‘7. 3. Approximate distance travelled by light in 1 year. 4. An exception is the US survey foot, shown in 2.6. 5. The legally defined chain, commonly called Gunter’s chain in the USA. 6. Also known as a statute mile. There is no recognized abbreviation for mile and the complete word ‘ mile ’ is used as the

7. Colloquial, for one-thousandth of an inch, 8. Colloquial, for one-thousandth of an inch. For ot!ier meanings of mil see 3.54.4 and (Note 2) of section 7. 9. Printing trade. (Originally defincd by 83 picas- 83 x 12 points = 35 cm).

10. Boot and shoe trade. 11. Button trade. 12. Watch trade. 13. Printing trade. 14. Height of horses. 15. Obsolete. 16. A nautical term not precisely defined in the UK. In ifs most general concept it is equal to one-tenth of an unspecified nautical mile, but other values have been used, including the value 120 fathoms (720 ft). 17. Obsolescent as the interiiational nautical mile becomes adopted in the UK. Foreonversion factors for a number of widely-used units of length see Table 2.

iinit symbol.

5


B S I BS*350: P A R T r L 74 m L b 2 4 b b î O L L b L 2 4 B m

BS 350 : Part I : 1974 Length

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6


3. Area (length squared)

3,1 The coherent SI unit of area is the square metre (symbol m2), a derived unit.

3,2 Areas are also expressed in terms of the squares of any of the multiples and submultiples of the metre formed by the use of the Si prefixes, e.g. square millimetre (mm2), square centimetre (cmz), square decimetre (dm2), square kilometre (km2),

i n accordance with the rule concerning prefixes attached to units raised to a power, the relationship between each of these and the square metre is as follows:

l d m * - (z) 2 = 10-2 in*

I km2 = ( i O 0 0 n 1 ) ~ = 106m*

1 a = 100m2 This, and more especially its multiple the hectare (symbol ha), are used for land measurement of area.

Another specially named metric unif is the barn, used in atomic physics in the measurement of cross

1 barn = 10-28 m?

3.3 A metric unit with a special name is the are (symbol a),

1 ha = 1ûOa = 1OO00m2

sections.

3.4 The connection between various traditional UK aiid US units of area, and their relationship to the square metre, are as foüows:

Refer to note I square foot (ft2) = 144 square inches (in21 (1 in2 1 square yard (yd2) = 9 square feet (1 ft2 = 0.092 903 O m2) 1 rood = 1210 square yards (1 yd2 = 0.836 127 m2) 1 1 acre = 4 roods = 4840 square yards (1 rood = 1011.71 m2)

(1 acre = 4046.86 m2) 1 square mile (mile2) = 640 acres (1 mile2 = 2.589 99 x 106 m*)

= 6.4516 x 10-4 m2)

3.5 A specialized UK and US unit of area (used in connection with sections of wire) is the ' circular inil '.

1 circular mil =--= 7.853 98 x 10-7 in2 = 5.067 07 X 10-10 m3 Refer to note

2 Notes on section 3 I , The rood is obsolescent in the UK and rarely used in the USA. 2. The circular mil has an area equal to that of a circle one-thousandth of an inch in diameter. For other meanings of mil see 2.6, 4.4 and section 7, Note 2.

For conversion factors for a number of widely-used units of area see Tables 3a and 36.

7


BS 350 : Part 1 : 1974 A’rea

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8


BS 350 : Part 1

1 circular mil* __ -_

1 square millimetre =

1 square inch -_

mm2

-_ in2

Volume and

circular mil square millimeíre square inch mm* in*

1 5.067 07 x 10-4 7.853 98 x 10 -7

1973.53 1 1.550 0 0 ~ 1 0 - 3

1.273 24x 106 645.16 1

: 1974 Area

capacity

4. Volume and capacity (length cubed)

4.1 The coherent SI unit of volume is the cubic metre (symbol m3), a derived unit.

4.2 Volumes are also expressed in terms of the cubes of any of the multiples and submultiples of the metre formed by the use of the SI prefixes; of these the cubic decimetre (dm9, the cubic centimetre (cmj), and the cubic millimetre (mm3) are common examples.

The relationship between each of these and the cubic metre is as follows:

3 1 mm3 = (6) = 10-9m3

4.3 Iii the SI no distinction is drawn between units of volume and units of capacity. However, a metric unit with a special name, used in conjunction with the SI and commonly used for the measurement of liquids and fluids, is the litre (symbol i?).

1 litre = 1 dm3 = 10-3 m3

(This definition has applied in the SI since 1964, but see 4.3.1 below.) The SI prefixes are used with the litre, leading for example to the hectolitre (hl), centilitre (ci), millilitre

(mi) and microlitre (pi). 1 hl = 100 litre =- 10-1 ni3

1 ci -= (&)litre = 10-srm3

i ml = (&)litre = 10-6 m3 = i cm3

I pl - - (&)litre -= 10-9 ln3 -- 1 mm3

4.3.1 Units of capacity for the measurement of liquids (and sometimes of dry goods also) have been treated as base units at various times in the past, and have been defined independently of length. Thus in the metric system from 1901 to 1964 the litre was defined as the volume occupied by a mass of one kilogram of water tAlfhough in this standard the symbol used for the litre is the lower case letter ‘I’, it has long been recognized that in some Asamende typefaces it was difficult to distinguish between the lower case letter ‘1’ and numeral 1. The 16th General Conference of Weights Jtrb19*3 and Measures (1979) accordingly recognized the use of the upper case letter ‘L‘ as an alternative symbol for the litre. In British Standards ‘L‘ is now the preferred symbol but ‘I’, which is still widely used, is recognized as acceptable. See also BS 5555.

9


BS 350 : Part I : i974 Volume and capacity

under specified conditions (at its temperature of maximum density and uiider a pressure of one standard atmosphere). Since 1964. however, the litre has been re-defined within the SI as a special name for the

slJIit[W/lY/ volume of one cubic decimetre (which is as it was before I901). Since 1 November 1976, the 1964 definition has been embodied within the law of {he United Kingdom. Because of these changes, where a very high degree of 1r/y / Y , t I

precision is called for, it is necessary to establish which definition of the litre is intended. In the tables which follow in this standard a litre as defined according to the 1901 definition is described as the 'litre (ISOI)', and the litre as it is now defined according to the SI is described simply as the 'litre'.

1 litre (1901) = 1.ooO 028 litre

4.4 In the French timber trade the volume of one cubic metre goes under the obsolescent name ' stère ' (symbol st). Similarly, in the timber trade in Germany the cubic metre has been described as the ' Festmeter (Fm) or ' Raummeter ' (Rm), and these two special names are also obsolescent.

Another obsolescent metric-based volume unit is the ' mil ', used in the UK in pharmaceutical work, particularly for prescriptions, to denote a millilitre (see British Phormncopoeia, 1953). For other meanings of ' mil ' see 2.6, 3.5, and section 7, Note 2.

4.5 The connection between the traditional UK and US iiiiits of volurne and their relationship to the cubic metre are as follows: Syml>ol Unit Metric equivalent

yd3 I cubic yard =: 27 cubic feet = 0.764 555 m3 ft3 1 cubic foot = 1728 cubic inches = 0.028 316 8 m j in 3 1 cubic inch = 1.638 71 x 10-5 1113

4.6 As with the litre in the metric system, it is customary to regard certain UK and US volumetric units as units of capacity. These include the UK gallon and its multiples and submultiples, and the US gallon and US bushel, with their multiples and submultiples. The UK and US units of capacity differ markedly from each other* and it is therefore important to avoid confusion in their use. The prefixes UK and US are used for purpose of their identification in this standard but the qualifications UK or US are frequently omitted in practice. Care is particularly necessary with conversions of the gallon in order to identify which gallon is concerned.

4.6.1 UK units qf cnpacity. These are all based on the UK gallon (UKgal), defined in Schedule 1 of the Weights and Measures Act, 1963, as the space occupied by 10 pounds weight of distilled water under certain conditions specified in the schedule. Key conversion factors are :

. ~ r d ~ + r ~ d Jfrli /YX.J

1 UKgal = 4.546 09 dm3 = 4.546 O9 litre = 4.545 96 litre (1901)

WKmin UK fl dr UK fl oz

UKpt UKqt UKgal

-

The connection between the UK gallon and its various multiples and subniultiples is shown in the I'ollowing list: Symbol (if any) Unit Metric equivalent

minim t = 0.059 193 9 cm3 fluid drachmt = 60 minim L= 3.551 63 cm3 fluid ounce = 8 fluid drachms = 28.4131 cm3 gill = 5 fluid ounces = 0.142 065 dm3 pint = 4 gills (= 20 fluid ounces) = 0.568 261 dm3 quart = 2 pints = 1.13652dm3 gallon = 4 quarts (= 160 fluid ounces) = 4.546 O9 dm3

- 1 peckf = 2 gallons - 1 busheit = 4pecks

= 9.092 18 dm3 = 36.3687dm3

4.6.2 U S units ofcapacity. The US units of capacity are defined in terms of a specified number of cubic inches. The US gallon is equal in volume to 231 cubic inches and is used for the measurement of liquids only. The US bushel is equal in volume to 2150.42 cubic inches and is used for the measurement of dry commodities only. * For a direct comparison of UK and US units of capacity see Table 4d

and it is now illegal to use these units for trade purposes. 8 « j J i t ~ r r d [ ~ d .I The minim, fluid drachm, peck and bushel are now deleted from Schedule 1 to the UK Weights and Measures Act, 1963; 'fr'yxj

10


BS 350 : Part 1 : 1974 Volume and capacity

The connection between the US gallon and its various multiples and submultiples is shown in the following list: 4.6.3 ü S utiits qf capacity (liquid measure only) Symbol (if any) Unit Metric equivalent - 1 US minim -- - 0.061 611 5 cm3 fl dr 1 US fluid dram* = 60 minims = 3.69669 cm3 us fl oz 1 US fluid ouncet = 8 fluid drams = 29.573 5cm3 gi 1 US gill = 4 fluid ounces = 0.118 294 dm3 liq pt 1 US liquid pint = 4 gills (= 16 ñuid ounces) = 0.473 176 dm3

USgal 1 US gallon = 4 liquid quarts(== 128 fluid ounces) = 3.785 41 dm3 bbl

liq qt 1 US liquid quart = 2 liquid pints - - 0.946353dm3

1 US barrel (for petroleum) = 42 gallons = 158.987dm3 4.6.4 US units of capacity (dry measure only). The connection between the US bushel and it5 various multiples and submultiples is shown in the following list: Symbol (if any) Unit hfcfric equivalent

-- 1 US dry pint I - 0.550 610 dm3 I US dry quart == 2 dry pints - - 1.101 2 2 ~ dry qt

Pk 1 US peck = 8 dry quarts = 8.809 76 dm3 bu 1 US bushel = 4 pecks = 35.2391 dm3 bbl (dry)

Notes on 4.6 I . In the UK different values are used for the barrel for differenf purposes (e.g. the wine barrel is nominally 3 1 $ UKgal and thc beer barrel nominally 36 WKgal). 2. The barrel (bbl) referred fo in the list of US capacity unifs for dry measure only is the standard barrel in the US for fruits. vegetables and dried commodities, with the exception of cranberries. Cranberriey are sold in the US hy reference to a standard cranberry barrel containing 5826 cubic inches. 3. There are otlier bushels having different capacities from those mentioned in 4.6. 4. Other specialized units of capacity used in the UK timber trade are

1 board foot = 144 in3 (= 2.359 74 dm3) 1 cord 1 standard

1 US dry barrel = 7056 cubic inches = 115.627 dmj

= 128 ft3 (= 3.624 56 m3) = 165 ft3 (= 4.67228 m3)

This last is sometimes known as the ' Petrograd standard 5. The cran, used in the UK fishing industry, is equal to 374 UK gallons.

For conversion factors for a number of widely-used units of volume or capacify see Tables 4a, 4b, 4c and 4d.

* So&tirnes also known as the liquid dram (liq dr) in the USA. f Sometimes also known as the liquid ounce (lis oz) in the USA.

11


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BS 350 : Part I : 1974 Volume and capacity

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14


BSI BS835Qs PART*L 7 4 I Lb24bb9 ~ RLlbL33 9 -~ ~~~ ~- _ _ ~ ~

üS 350 : Part 1 : 1974 Volume and capacity

Modulus of section Second moment of area

Table 46. Relationship.between UK (imperial) and US units of capacity

1 UK minim = 0.960 760 US minim 1 UK fluid drachm = 0.960 760 US fluid* dram 1 UK fluid ounce = 0.960 760 US fluidf ounce 1 UK gill = 1.200 95 US gill 1 UK pint = 1.200 95 US liquid pint I UKquart = 1.200 95 US liquid quart 1 UK gaiion = 1.200 95 US gaiion 1 UK pint = 1,032 06 US dry pint 1 UK quart = 1.032 06 US dry quart

1 UK bushel = 1.032 06 US bushel

1 US minim == 1.040 84 UK minim 1 US fluid' drain =-z 1.040 84 UK fuid drachm 1 US fluidt ounce = 1.040 84 UK fluid ounce 1 US gill = 0.832 674 UK gill 1 US liquid pint = 0.832 674 UK pint 1 US liquid quart = 0.832 674 UK quart 1 US gaiion 0.832 674 UK gallon 1 US dry pint = 0.968 939 UK pint 1 US dry quart = 0.968 939 UK quart

1 US bushel = 0.968 939 UK bushel

1 UKpeck = 1.032 06 US peck

1 US peck = 0.968 939 UK peck

* Sometimes also known as the liquid dram in the USA. t Sometimes also known as the liquid ounce in the USA.

1m4 =

lcm4 =

1 ft4 =

--

o

m4

1

1 x 10-8

0.863 097 x 10-2

5. Modulus of section, first moment of area 5.1 These quantities have the same dimensions as volume; the coherent SI unit is therefore the metre cubed (m3). 5.2 They may also be expressed in terms of thetcube of any suitable submultiple of the metre; the centimetre cubed (cm3) and millimetre cubed (mm3) are commonly used. 5.3 In imperial units the foot cubed (ft3) or inch cubed (in3) are usually used.

The relationship between the above-mentioned uniís can be seen or inferred from Table 4a.

6. Second moment of area, or geometrical moment of inertia The coherent SI unit for this quantity is the metre to the fourth (m4). Other commonly used units are the centimetre to the fourth (cm41 and millimetre to the fourth (mm4) and, in imperial units, the foot to the fourth (ft4) and inch to the fourth (in4). See Table 6 for conversion factors for these units.

Table 6. Second moment of area

1 in4 = I 41.6231 x 10-8 NOTE. 1 mm4 = 10-4 cm4 = 10-12 m4.

I 1

1 x 108 115.862 2 402 510

1.15862 x 10-6

863 097

41.6231 I 4.822 53 x 10-5 I 1

15


. BSI BS*350: P A R T * i I 74 I i1624669 OiI16134 O I

BS 350 : Part I : 1974 Plane angle

7. Plane angle

7.1 The coherent SI unit of plane angle is the radian (symbol rad), a supplementary" unit. It is the angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius.

Thus a complete circle subtends an angle of 2n: rad at its centre, and a riglit angle (L) equals 2x x -rad = - rad. 4 2 7.2 Angular units of such practical importance that they are retained for general use in conjunction with the SI are the traditional units degree ( O ) , minute ('), second (").

The full circle subtends an angle of 360 degrees (360') at its centre, and thus the right angle (L) = 90 degrees (90 O).

x 1 degree (1 O) = 60 minutes (60') = -rad 180

rad x 60 i< 180 1 minute (I') = 60 seconds (60") =

1 second (1") I C - -

3600 x 180 rad

It is often convenient to express sub-divisions of the degree in decimal form, rather than to use minutes and seconds. 7.3 A unit of plane angle used in some continental countries is the grade (3 or, as it is called in Germany, the gon. This is a one-hundredth of a right angle.

x lo (or 1 gon) = 0.9" - -rad - 200

Notes on section 7 1. Note the possibility of confusion between the hundredth part of a grade in angular measure and the terni Centigrade (cor- rectly called Celsius) in connection with temperature, 2. The unit ' mil ' is sometimes used in connection with angular measure. For sonie purposes the angular mil is taken to be one thousandth of a radian (10-3 rad), which is equivalent to 3'26.25". There is, however, anuther concept iii which an angular mil is equal to 360/6400 degrees ¡.e. 3' 22.5". For other meanings of ' mil ' see 2.6, 3.5, and 4.4. 3. In English there is no commonly used expression for the ' full angle ' siihiended by a circle. In German the terni ' Vollwinkel ' is used.

For interconversion factors for the units mentioned in 7.1,7.2 and 7.3 see Table 7.

Table 7. Plane angle Exact values are printed in bold type.

radian rad

1 - 1 radian - rad

i right angle = 1.570 80

1 degree = 0.017453 3 0

1 minute = 2.908 88 X 10-4

1 second = 1 4.848 14x10-6

1 grade (or gon) = 0.015 708 O P gon

right angle L

0.636 620 57.2958

I 1

I l 0.011 111 1

1.851 85x10-4 0.016 666 7 . I 3.08642~10-6 2.777 78x10-4

0.01 0.9

minute , ~ - I

3437.75

5400

60.

1

0.016 666 7

54

second ,,

206 265

324 O00

3600

60

1

3240

grade (or gon) P gon

63.6620 ..

____ 100

1.111 11

1.851 85 x 10-2

3.086 43 x 10 -4

1

. ~ . ~ n m w d d * In October 1980 the International Committee of Weights and Measures decided to interpret the class of supplementary units in Ji'b198J the Intemational System as a class of dimensionless derived units for which the General Conference of Weights and Measures

leaves open the possibility of using these or not in expressions ofderived units ofthe International System.

16


8. Solid angle

BS 350 : Part 1 : 1974 Solid angle

Time Linear velocity

The coherent unit of solid angle, the only unit in common use for solid angle, is the steradain (symbol sr), a supplementary* unit. It is the solid angle which, having its vertex a t the centre of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.

9. Time 9.1 The SI unit of time is the second (symbol s), a base unit. It is now defined as the duration of a specified nuniber of periods of a particular atomic radiation; for details see BS 3763. 9.2 Prior to 1967 the second was defined as a speciiìed fraction of the time taken by the Earth to complete a particular orbit of the Sun. (This second, the ' ephemeris second ', is retained for use as a special unit in astronomy, and is as nearly equal to the SI unit as the highest precision of measurement could permit in 1967.) 9.3 Other units of time of such practical importance that they are retained for general use in conjunction with the SI are:

minute (min) hour (h) I h = 60 min = 3600 s

A complete sphere subtends a solid angle of 4n sc at its centre.

1 min = 60 s

day (d) I d =24h = 8 6 4 0 0 ~ 9.4 Longer durations of time are conveniently expressed in terms of the week, month or year, but the last two of these cannot in general be explicitly related to the second (of time).

lweek = 7 d = 604800s 1 Month = 28, 29, 30 or 31 days (according to calendar) 1 yearf = 12 months = 365 or 366 days (according to calendar)= 8760 h or 8784 h (according to calendar). .qrnJllt.il

J11[r IYX3 Notes on section 9 1. The only time unit commonly used in conjunction with the SI prefixes is the second; e.g the submultiples millisecond (nu), inicrosecond (cis) and nanosecond (ns) which are in wide technological use. 2. The symbol a ' is used for year. 3. The scale of International Atomic Time (TAI), based directly on the atomic radiation defining the second, is maintained by .+ U < / M the Bureau International de l'Heure (BIH) in Paris. Legal time in the UK, as in most countries, is based on a related scale, that of Jdi.I583 Co-ordinated Universal Time (UTC), broadcast by an international network of radio stations. UTC is defined in such a manner that it differs from TAI by a whole number of seconds. The difference UTC-TAI was set equal to - IO s on 1 January 1972, the date ofapplication ofthe reformulation of UTC (which previously invoived a frequency offset). This difference can be changed in steps of 1 s, but the use of a positive or negative leap second at the end of a month of UTC, preferably in the first instance at the end of December or of June, and in the second instance at the end of March or ofSeptember, to keep UTC in agreement with the time defined by the rotation of Earth with an approximation better than 0.9 s. On 1 January 198 1 the difference UTC-TAI was - 19 s. in fact, the legal times ofmost countries are offset from UTC by a whole number of hours (because of time zones and 'daylight saving' arrangements).

I O. Linear velocity (speed) (length/time) 10.1 The coherent SI unit of linear velocity is the metre per second (symbol m/s), a derived unit. 10,2 Multiples and submultiples of the metre per second are formed by using any of the SI prefixes in conjunction with the metre. 10.3 A metric unit often used for speed is the kilometre per hour (km/h).

1 km/h = 0.277 778 m/s 10.4 Various speed units used in the imperial system are:

foot per second 1 ft/s = 0.3048 m/s inch per second 1 in/s 0.0254 m/s foot per minute mile per houri

The international knot (kn) is metric-based, being equat to one international nautical mile per hour. 1 kn = 1852 m/h = 0.514 444 m/s The UK knot is imperial-based and obsolescent, king equal to one UK nautical mile per hour. 1 UK knot = 6080 ft/h = 0.514 773 m/s

1 ft/min = 0,005 O8 m/s 1 mile/h = 0.447 04 m/s

10.5 The knot, one nautical mile per hour, is a unit used for speed in nautical and aeronautical contexts.

Por interconversion factors for the above units see 'fable 10. * In October 1980 the International Committee of Weights and Measures decided to interpret the crass of supplementary units in .Jslmettdtv/ the International System as a class of dimensionless derived units for which the General Conference of Weights and Measures Jir!i.IY*3 leaves open the possibility ofusing these ornot in expfessions ofderived units ofthe International System. t The year referred to here is the ' d e n d a r y&'. Calendar adjustments are based on the ' tropical year ', the tiTe interval between two consecutive passages (in the same direction) of the Sun through the Earth's equatorial plane, In 1900 the duration of the ' fropical year ' was 365.242 198 78 d and it is decreasing at the rate of 6.14 x 10-6 days per century. $ Traditionally indicated by the abbreviation m.p.h.

17 COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

B S I BS*350: P A R T * & 74 m Lb24bb9 OlLbi13b 4 m

BS 350 : Part I : 1974 Linear velocity

18


B S I L S * 3 5 0 { PART83 -~ ~~ 74 m 3624669 0336137 =- -~

BS 350 : Part I : 1974 Angular velocity

Frequency 11. Angular velocity" (angle/time) 11.1 The coherent SI unit of angular velocity is the radian per second (rad/s), a derived unit. 11.2 Other units used are:

radian per minute (rad/min) revolution per minute revolution per second degree per minute ("Imin) degree per second "Is)

(revlmin) or (r/min) (revis) or (rid

For interconversion factors for the above units see Table 11.

Table 11. Angular velocity and velocity of rotation Exact values are prinfed iii bold type

second minute rev/min

60 9.549 30

-_l-l

1 0.002 652 58 0.159 155

radian per second md/s --- - - -_

1 radian pcr sccond

1 radian per miiiiice = 0.016 66U 7

= = ~ 1 radis

radlniin

I 57*2958

I 1 revolution per second = 6.283 i9 376.991 1

rcv/s

rev/niin 1 rcvolution per minute = 0.104 720 6.283 19 0.016666 7

- I degree per secoiid = 0.017 453 3 1.047 20 0.002 777 78 0.166 667

"Is

2.908 8 8 x 1 0 4 0.017 453 3 4.629 63 XlO-5 2.777 78x10-3 0.016 666 7 =I l l I I degree per minute "/ni in

12. Frequency (numberJtime)

degree per minute '/min

3437.75

57.2958

21 600

360

60

1

12.1 The coherent SI unit of frequency (of a wave or periodic phenomenon) is the hertz (symbol Hz), a derived unit with a special name. Formerly in this country the hertz was called the cycle per second (CIS). Expressed in terms of base units of the SI both the hertz and the cycle per second are the inverse second i.e, - (or s -1).

12.2 The coliereiif SI unit of rotational frequency (e.g. a frequency associated with the mechanical rotation of a shaft) is also the inverse second, i.e. - (or s -1). It is commonly known as the revolution per secoiid

(re;/s or r/s). 12.3 Another very commoiiíy used unit of rotational frequency is the revolution per minute (revlmin or r/min, but traditionally indicated by the abbreviation r.p,m.).

1 S

1 S

1 60 1 'iev/min = - rev/s

1 1 60s 60 = (in SI terms) - or - s-1

12.4 Corresponding angular velocities are obtainable from Table 11 using 1 rev,ís as corresponding to 1 Hz, 1 - or s-1. S

NOTE. See also the note under secfion 11, Angular velocity.

* Thc terms ' rotational velocity', ' rotational speed ' and ' speed of rotation ' are commonly used as alternative terms for aiigulat velocity, but are also often thought of as a frequency, particularly when being expressed in revolutions per minute, or per second. When frequency is meant, the revolution should not be identified with ande as it is 9 0 identified in Table 11 (1 revolution = 2 'IC radians = 360 O), but should be thought of as a number, and a clearer fe rn for expressing this concept is ' rotational frequency '. (See also section 12, Frequency,)

19


B S I BS*350: PART*L 74 m Lb24bbî OLbb&38 8 m

BS 350 : Part 1 : 1974 Acceleration Mass

13. Acceleration (length/time squared) 13.1 The coherent SI unit of acceleration is the metre per second squared (symbol m/s2), a derived unit. 13.2 The centimetre per second squared (cm/s2), a submultiple of the above, is also called the galileo or gal (symbol Gal).

1 Gal = 1 cm/s2 = 10-2 m/s2 A unit that has been commonly used in geodesy is the milligal (mGal). 1 mGal = 10-3 Gal = 10-5 m/s2

1 ft/s2 = 0.3048 m/s2 13.3 The most-used unit in the imperial system for acceleration is the foot per secoiid squared (ftls2).

13.4 The standard acceleration of 9.806 65 m/s2 plays an important part in the definition of certain iinif in the older technical systems. When the acceleration of free fall has this value the terin ' standard gravity ' is used, the associated symbol for this quantity being g,,.

The acceleration due to gravity is sometimes used as a unit of acceleratioii, and called ' g ', particularly in aeronautical engineering and centrifuge technology. For the sake of precision the standard value 9,806 65 m/s2 should be taken for this unit, A close approximation in imperial units is 32.1740 ft/s2. These are frequently rounded to 9.81 m/s2 and 32.2 ft/s2. Interconversion factors for the above units can be seen or inferred from Table 13.

Table 13. Acceleration Exact values are printed in bold type

i metre per second squared = m/s2

metre per second squared m/s2 - -_-

3, 1 foot per second squared = 0.3048

ft/s2

standard acceleration due to gravity = 9.806 65 gn I

NOTE. 1 Gal = 1 m/s2 = 10-2 m/s2 1 mGal - 10-5 m/s2 (see 13.2).

foot per second squared ft/s2

3.280 84 .- - - . - . -

-

1

32.1740

standard acceleration due to

¿?n grallitY

~. - . . . . -. -

0.101 972

_______ -. ....

0.031 081 O

1

14. Mass 14.1 The coherent SI unit of mass is the kilogram (symbol kg), a base unit. It is defined as equal to the mass of the international prototype of the kilogram (which is in the custody of the International Bureau of Weights and Measures at Sèvres near Paris).

14.2 Because the name of the base unit of mass already contains the SI prefix ' kilo ', multiples and submultiples are formed by adding SI prebes to the word ' gram '. Examples are megagram (Mg), gram (g), milligram (mg) and microgram (pg), as follows:

Refer to note 1 M g = 1000kg -

I

1 lo00 l g =-kg

1 mg = 10-6kg I

i pg = 10-9kg I In practice the megagram is usually referred to by the special name ' tonne ' (symbol t), and is often

called the ' metric ton ' in the UK and in the USA.


BS 350 : Part 1 : 1974 Mass

14.3 Some other units of mass having associations with the metric system are:

1 metric carat = 200 milligrams = 2 x 10-4 kg 1 quintal (q) = 1ûOkg 1 atomic mass unit (u) = 1.660 53 X 10-27 kg

Refer to note 2

- 14.4 The primary unit of mass in the imperial system and in the USA is the pound (Ib). In the UK Weights and Measures Act, and in similar legislation in the USA, it is defined precisely and exactly as fdows:

14.5 The connection between multiples and submultiples of the pound is indicated in t b following traditional lists of named UK and US units of mass,

1 lb = 0.453 592 37 kg

Avoirdupois units (a) UK and US units 1 pound = 16 ounces (OZ) (1 OZ = 28.3495 g)

= 16x 16 drams (dr) (1 dr = 1.771 85 g) = 7000 grains (gr) (1 gr = 0.064 798 91 g)

(b) UK units only 1 stone = 14pounds (= 6.350 29 kg) 1 quarter (qr) = 28 pounds (= 12.7006 kg) 1 cental (cfl) = 100pounds (= 45.3592 kg) 1 hundredweight (cwt) = 112 pounds (= 50.8023 kg) 1 ton (ton) = 2240pounds (= 1016.05 kg) (c) US units only 1 short hundredweight (sh cwt) = 100 pounds (= 45.3592 kg) 1 short ton (sh ton) = 2000pounds (= 907,185 kg) (In the USA the word ton refers to the ' short ton ' of 2000 lb unless otherwise specified. The terms ' long

ton ' or ' gross ton ' are sometimes used, referring to the ton of 2240 lb. The hundredweight of 112 lb is often called the ' long hundredweight '. The use of the ' long units is decreasing in the USA.)

Apothecaries' unifs (used in the UK* and the USA) 1 scruple" = 20 grains (= 1.295 98 gram) 1 drachm* (in UK) = 3 scruples (= 3.887 93 gram) 1 dram (in USA) = 3 scruples (= 3.887 93 gram) 1 ounce* = 24 scruples = 480grains (= 31.1035 gram)

(oz apoth in UK oz ap in USA)

Troy units (used in the UK and the USA) 1 ounce troy = 1 apothecaries' ounce = 480 grains (= 31.1035 gram)

(oz tr in UK oz t in USA)

(The apothecaries' ounce* and the ounce troy are identical in mass and differ from the avoirdupois ounce. Unless otherwise qualified, the term ounce and ifs abbreviation oz signify the ayoirdupois ounce. The pound troy has 110 legal basis in the UK but i s legalized in the USA, where it is defined as a mass equal to 5760 grains.

1 pound troy (USA only) = 12 ounces troy = 5760 grains (= 0.373 242 kg) The grain has the same value in the avoitáupois, troy, and apothecaries' systems, and is abbreviated to

gr in the UK.) 14.6 S o i e more specialized UK and/or USA iianied units of mass are:

= 32.667 g = 29.166 g

I assay toi1 (UK) 1 assay ton (US) 1 slug = 32.1740 lb (= 14.5939 kg) 1 international corn bushel = 60 lb (= 27.2155 kg)

Refer to noíc

3 4 5 6

For interconversion factors for inany of the Units of mass mentioned above see Tables 14u, 146 and 14c.

* The apothecaries' uiiits (scruple, drachm, and apothecaries' oance) have been illegal since 1 January 1971 for use in the United Kingdom.

21


BSI BS*350: PARTUL 7 4 Lb24669 OLLbL40 b

BS 350 : Part I : 1974 Mass

Notcs on section 14 1. The alternative name ' gamma ' (symbol y) is somctimes uscd to indicate a micrograin. 2. The metric carat has international sanction for use in trade in diamonds, fine pearls, and precious stones. Iii tlie UK tlie Icgiil abbreviation for this unit is CM. 3. The number of milligrams in a UK assay ton is equal to the number of ounces troy in a UK ton. 4. The number of milligrams in a US assay ton is equal to the number of ounces troy in a US (short) ton. 5 . The slug is tlie British technical unit of mass. One pound-force acting on this mass produces an accelcratioii of I foot per second squared. 6. Used for the salc of wheat iindcr internatioiial Whent Agrecment, 1949.

Table i4a . Mass Exact values are printed in bold type.

1 kilogram kg I 2.204 62 I o.o68 521

1 pound Ib I l = 0.453 592 37 I 08' O

I slug = I 14.5939 32.1740

22



U

W \o Q\ W in

8

oo 2 U U

9 O

m G! 8

Q\ F s VI

O 00

d. ril

G W m 8

O 3

Y e u Li I ._ 2

io o\ Q\ m a O c?

2 x in U

23



e4 v! 8 M -


B S I BS3350: P-ART*i 74 E 1624669 OlLbi43 i E __________- -~ -__ ~ _ _ ~ ~ - --

BS 350 : Part I : 1974 Mass per unit length

15. Mass per unit length (or linear density) (masdlength)

15.1 The coherent SI unit of mass per unit length is the kilogram per metre (symbol kg/m), a derived unit. 15.2 Two specialized units of linear density used in the textile industry and which have an association with the metric system are:

1 tex = 1 gram per kilometre = 10-6 kg/m 1 denier = 1 gram per 9 kilometres = 0.111 112 x 10-6 kg/m

1 pound per inch (lb/in) 1 pound per foot (lb/€t) (= 1.488 16 kg/m) 1 pound per yard (lb/yd) (= 0.496 055 kg/m) 1 pound per mile (lb/rnile) 1 UKton per loo0 yards (ton/lûûû yd) 1 UKton per mile Cton/mile) (= 0,631 342 kg/m)

15.3 A selection of imperial units used in industry, often for Wires, rods etc. is: (= 17.8580 kg/m)

(= 2.818 49 X 10-4 kg/@ (= 1.11 1 16 kg/m)

Interconversion factors for the units in 15.1 and 15.3 are given in Table 15. For further information on 15.2 reference should be made to BS 947 which gives tables for calculating the tex values of numbers or counts in other systems, including denier.

e

25


BSI BS*350: PART*L

BS 350 : Part I : 1974 74 811 Lb24bbï OLlb144 3 =

Mass per unit length

t I

E: x o\ i.1

o -

8 z 06

m

r(

N w m æ 9 E;

r(

m m m m m 2

io m io m io m 8

m m m m

03 cc F s 8

in

W 8 3 II

2 R I4

a fia g-h ns d

1 Li

B E

B E n r "

E O0

3 d - II

k

F1 a fi g $ nf d

26


BS 350 : Part I : 1974 Mass per unit area

16. Mass per unit area (mass/length squared) (applicable for example to sheet metal, plating etc., and in agriculture)

16.1 The coherent SI unit is the kilogram per square metre (kg/m2), a derived unit. 16.2 Other commonly used metric units are:

gram per square metre (g/m2) milligram per square centimetre (inglcm2) milligram per square millimetre (nig/mm*) kilogram per hectare (kg/ha)

16.3 A selection of imperial units is: pound per thousand square feet (lb/lûûO ft2) ounce per square yard (ozlyd2) ounce per square foot (oz/ft2) pound per acre (lb/acre) UK ton per square mile (ton/milez)

(= 0.001 kg/m2) (= 0.01 kg/m2) (= 1 kg/m2) (= O.ûûO1 kg/m2)

(= 4.882 43 X 10-3 kg/mz) (= 3.390 57 x 10 -2 kg/m2) (= 0,305 152 kg/m2) (= 1.120 85 x 10-4 kg/m2) (= 3.922 98 x 10 -4 kg/m*)

For interconversion factors for the above see Table 16.

27


BS 350 : Part I : 1974 Mass per unit area

O0 o\

M 2

iA u O0 ?

T: a 4

4 CI

i! 3

r.

O0 9 2 d

2 m I O 4

X O0 iA m O0 c'! CI

e4

E 5 CI

I

5 . . x -

n

f 5

II

Fi

2 i

28


-~ BSI ~- BSU350: PART-*& 74 l b 2 4 b b ï OLLbl47 9

BS 350 : Part I : 1974 Area per unit mass

17. Specific surface, or area per unit mass (applicable to sheet metal, plating, etc., and in agriculture)

17.1 The coherent SI unit is the square metre per kilogram (m2/kg), a derived unit. 17.2 Other commonly used metric units are:

square metre per gram (m2/g) (= loo0 m2/kg) square centìmetre per milligram (cm2/mg) (= 100 m2/kg) square d m e t r e per milligram (mm2/rng) (= 1 mz/kg) hectare per kilogram (ha/kg) (=IO o00 m21kg)

thousand square feet per pound (1000 €t2/ib) (= 204.816 rnz/kg) square yard per ounce (yd2/oz) (= 29.4935 mykg) square foot per ounce (ftyoz) (= 3.277 O6 mz/kg) acre per pound (acrelib) square mile per UK ton (milezlton)

173 A selection of imperial units is:

(= 8921.79 mykg) (= 2549.08 m2/kg)


30 ,-- -.

Previous page is blank


rr ) I

s

d

X io @-I

a

* I

o, i? 2

X d

\o O t- t-

2 2

Area per unit mass

O

O

* I

s x ril ril

O0 Q\ Cu Cu

2 Y 0

io O0

O N d

sì F 09 t-

i 2 CO

t- io O Q\ @-I m 8 m I

2 G

2

X

N CO

ril d

? O

O

O

II i II

31


- I.--

1 square yard per gallon

1 square foot per gallon

-- Y d2/gal

ft2/gal

I =

BSI BS*350: P A R T * 3 'i4 = 3624bb9 0336349 2 =

0.183 992 1 . 9

0.020 435 8 0*111 111 1

BS 350 : Part 1 : 1974 Area per unit capacity Density 18. Area per unit capacity Another combination with somewhat similar application is ' area per unit capacity (used for the ' covering power ' of paints, etc.). Table 18 gives interconversion factors for square metres per litre, square yards per UK gallon, and square feet per UK gallon.

Table 18. Area per unit capacity I l I

I --I I

1 48*9337 1 square metre per litre m2/l

19. Density * (mass/volume) 19.1 The coherent SI unit of density is the kilogram per cubic metre (kg/m3), a derived unit. 19.2 Other commonly used metric units are:

(= loo0 kg/m3)

(=27 679.9 kg/m3) (= 16.0185 kg/m3)

gram per cubic centimetre (g/cm3) or gram per millilitre (g/ml)t

pound per cubic inch (lb/in3) pound per cubic foot (lb/ftJ) UK ton per cubic yard (UKton/yd3) (= 1328.94 kg/mJ) pound per UK gallon (lb/UKgal) (= 99.7763 kg/m3) pound per US gallon (Ib/USgal) (= 119.826 kg/m3)

} 19.3 A selection of imperial units is:

For interconversion factors for the above see Table 19. See also section 20, Concentration,

* It should be noted that ' relative density ' (i.e. density/reference density) is a dimensionless quality. The relative density of a substance is defined as the ratio of the mass of a given volume of that substance to the mass of an equal volume of a reference substance, under conditions which should be specified for both substances.

When the reference substance is water the term ' specific gravity ' is commonly used for relative density. For conversions of readings of hydrometers on different density and specific gravity bases see BS 718, i 1 gram per millilitre (1901) = 999.972 kg/mJ. See 4.3, litre,

32


BS 350 : Part 1 : 1974 Density

N I

IC :

I I

I

x O Do

t- Y - m I

X E

8 rn N c? d

g c

W li

in Do 8 2 8

I I I I

II

33


BSI BS*350: P A R T * l 74 Lb2Ybbî QLLbL54 0 m- BS 350 : Part 1 : 1974 Concentration

20. Concentration (mass/volume)

20.1 The coherent SI unit for the expression of concentration* (in the sense of the mass of a substance per unit volume of a solution, or the like) is the kilogram per cubic metre (kg/d) , a derived unit. This unit is equaf to 1 gram per cubic decimetre, and is commonty expressed as 1 gram per litref'. 1 kg/m3 = 1 g/dm3 = 1 g/1

20.2 Some imperial and US units which are in practical use for the statement of coiicentratioii are: grain per cubic foot (gr/ft3) (= 0.228 835 x 10-2 kg/in3) grain per UK gallon (gr/UKgal) (= 0.014 253 8 kg/m3) grain per US gallon (gr/USgal) (= 0.017 118 1 kg/m3) ounce per WK gallon (oz/UKgal) (= 6.236 02 kg/mJ) ounce per US gallon (oz/USgal) (= 7,489 15 kg/m3)

For interconversion factors for the above see Table 20. See also section 19, Density.

* Concentration is sometimes expressed in other ways, for example, mass (of a substance) per unit mass (of a solution), or, in physical chemistry, in terms of moles per unit volume, t 1 gram per litre (1901) = 0.999 972 kg/m3. See 43, litre.

.

34


BS 350 : Part I : 1974 Concentration

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B S I BS*350: PART*KL 7 4 l b 2 4 b b î O l l b l 5 3 4 m

BS 350 : Part I : 1974 Specific volume

I 21. Specific volume (volume/mass)

21.1 The coherent SI unit of specific volume (which is the reciprocal of density) is. the cubic metre per kilogram (mj/kg), a derived unit. 21.2 Anothcr commonly used metric unit is:

litre* per kilogram (l/kg) = 0.01 m3/kg. 21.3 A selection of imperial units is:

cubic foot per pound (ft3/lb) cubic inch per pound (in3/lb) cubic foot per UK ton (ft3lUKton) UK gallon per pound (UKgal/lb)

(= 0,062 428 O m3/kg) (= 3.612 73 x 10-5 m3/kg) (= 2.786 96 x 10-5 mJ/kg) (= 0.010 022 4 rnJ/kg)


* 1 litre (1901) per kilogram = 1.ûûû 028 x 10-3 mi/kg. See 4.3, titre.

36


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BS 350 : Part1 : 1974 I Specific volume


- _ - .

BsI BS*350: P A R T * L 74 Lb24bbq O J , L ~ J ~ ~ S

BS 350 : Part I : 1974 Mass rate of flow Volume rate of flow 22. Mass rate of flow (masc/time)

22.1 The coherent SI unit of mass rate of flow is the kilograin per second (kgls), a derived unit. 22.2 Another commonly used metric unit is the kilogram per hour (kg/h).

1 kg/h = 2.777 78 x 10-4 kg/s 22.3 A selection of imperial units is:

pound per second (Ib/s) pound per hour (lb/h) UK ton per hour (UKton/h)

(= 0.453 592 kg/s) (= 1.259 98 x 10-4 kg/s) (= 0.282 235 kg/s)


Table 22. Mass rate of flow Exact values are printed in bold type.

kilogram per second

1 kilogram per second = 1 kg/s

k d h 1 kilogram per hour = 2.777 78x 10-4

1 pound per second = 0.453 592 lb/s

1 pound per hour = 1.259 98 x 10 -4

Ib/h

1 UK ton per hour = 0.282 235 UKton/h

kilogram per pound per hour second

lb/s --

kdh

3600 2.204 62

1 6.123 95x 10-4

I l 1632.93

0.453 592 2.777 78 x 10-4

1016 .O5 0.622 222

I

pound pr UK ton per hour how lb/h UKton/h

7936.64 3.543 14

_.I._

2.204 62 9.842 07 x IO -4

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1 4.464 29 x 10 - 4

2240 1

I

23. Volume rate of flow" (volume/time)

23.1 The coherent SI unit of volume rate of flow is the cubic metre per second.f. (d/s) , a derived unit. 23.2 Some other commonly used metric units are:

cubic metre per hour (m3/h) litre# per second (@I litre# per minute (I/min) litre# per hour (I/h)

cubic foot per secondg (ft3/s) cubic foot per hour (ft3/h) UK gallon per second (UKgal/s) UK gallon per minute (UKgal/min) UK gallon per hour (UKgal/h)

(= 2.777 78 x 10-4 m3/s) (= 0.001 m3/s) (= 1.666 67 x 10-5 m3/s) (= 2.777 78 x 10-7 m3/s)

(= 0.028 316 8 1n3/s) (= 7.865 79 x 10-6 m3/s) (= 4.546 O9 x 10-3 in3/s) (=: 7.576 82 x 10-5 m3/s) (= 1,262 80 x 10-6mJ/s)

23.3 A selection of imperial units is:


* For gases, the conversion factors given here are based on the ussiiniption that the reference conditions of temperature, pressure and humidity remain unchanged.

$ The litre (1901) = 1.OOO 028 litre (see 4.3). 5 The cubic foot per second is sometimes known as the ' cusec '.

The cubic metre per second is sometimes known as the ' cumec ',

38


BS 350 : Part 1 : 1974 Volume rate of flow

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E S 1 BS*350: P A R T * L 74 1624bb9 Ollb157 1

BS 350 : Part I : 1974 Traffic factors

24. Traffic factors (in connection with volume of fuel consumed, distance run and load carried)

It should be noted that in European countries fuel consumptions are usually expressed in terms of litres per kilometre, or litres per 100 kilometres, i.e. volume of fuel per distance run (see Table 244. In the UK the reciprocal factor (distance/volume) in terms of miles per gallon is used (see Table 24b). Figure 1 is a graph indicating the relationship between litres per 100 kilometres and miles per gallon, over the range 10 miles to 100 miles per gallon.

Table 24a. Fuel consumption (voIume/distance) Exact values are printed in bold type.

I ütritrper kilometre* UK gallon per mile UKgal/mile USgal/mile

US gallon per mile

1 litre per kilometre* = I 1 I 0.354 006 I 0.425 144 l/km

1 UK gallon per mile = 2.824 81 1 1.200 95 UKgal/mile

-

1 US gallon per mile = 2.352 15 0.832 674 1 USgal/mile

* Several European countries use the factor ' litre per 100 kilometres '.

Table 246. Fuel consumption (distance/volume) Exact values are printed in bold type.

kilometre per litre h l i

1 2.824 81 2.352 15

miie per UK gallon mile/UKgal mile/USgal

mile per US gallon

1 kilometre per litre = km/l

1 mile per UK gallon 0.354 006 mile/UKgal

0.832 674

= I 1 mile per US gallon mile/USgal

1.200 95

Mass carried x distance 1 tonne kilometre 1 UKton mile = 1.635 17 tonne kilometre

Mass carried x distance/volume 1 tonne kilometre per litre 1 UKton mile per UK gallon = 0.359 687 tonne kilometre per litre

= 0.611 558 UKton mile

= 2.780 20 UKton mile per UK gallon

40


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BS 350 : Part I : 1974 Traffic factors

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41


BSI BS*3CO: P A R T * l 74 131 1624bb9 Oll6359 5

BS 350 : Part I : 1974 Moment of inertia Momentum Angular momentum 25. Moment of inertia (mass x length squared)

25.1 The coherent SI unit of moment of inertia is the kilogram metre squared (kg m2), a derived unit. 25.2 Some other metric units which have been used are:

kilogram miliimetre squared (kg mm2) gram centimetre squared (g cm2)

25.3 A selection of imperial units is: pound foot squared (íb ft2) pound inch squared (Ib in2) ounce (avoir) inch squared (oz in2)

(1 kg mm2 = 10-6 kg m2) (1 g cm2 = 10-7 kg m2)

(= 0.042 140 1 kg m2) (= 2.926 40 x IO -4 kg m2) (= 1.829 O0 x 10-5 kg m2ì


Table 25. Moment of inertia Exact values are printed in bold type.

kilogram metre pound foot pound inch ounce inch

kg m2 squared squared squared lb ft2 Ib in2 oz in2

s q d

1 kilogram metre squared = 1 23,7304 3417.17 54 674.8 kg m2

1 pound foot squared = 0.042 140 1 1 144 2304 lb ft2 -

1 pound inch squared = 2.926 40 x 10 -4 6.944 44 x 10 -3 1 16 íb in2

-- 1 - 1 ounce inch squared - 1.829 O0 x 10 -5 4.340 28 x IO -4 0.0625

oz in2

NOTE. 1 kg m2 = 106 kg mm2 = 107 g cm2,

26. Momentum (linear) (mass x velocity) The coherent SI unit of momentum is the kilogram metre per second.

Some key conversion factors are: 1 kg m/s = 7.233 O1 lb ft/s 1 Ib ft/s = 0.138 255 kg m/s (1 kg m/s = 105 g cm/s)

27. Angular momentum (mass x velocity x length) The coherent SI unit of angular momentum is the kilogram metre squared per second.

Some key conversion factors are : 1 kg 1 Ib ftz/s = 0.042 140 1 kg m2/s

;= 23.7304 Ib ftz/S

42


BS 350 : Part 1 : 1974 Force

28. Force (mass x acceleration)

28.1 The coherent SI unit of force is the newton (N), a derived unit with a special name. Expressed in terms of base uiiits of the SI the newton is the kilogram metre per second squared (kg m/s2) and is that force wliicli, when applied to a body having a mass of one kilogram, gives it an acceleration of one metre per second squared. 28.2 Other metric units of force of historical or practical importance are:

the dyne (dyn), the force unit in the centimetre-gram-second system, the sthène (sn), the force unit in the metre-tonne-second system, and the kilogram-force (kgf), which is often described as the metric technical unit of force. In Germany and some other continental countries the kilogram-force is called the kilopoiid (with symbol kp).

1 dyn = 1 g cm/s2 1 sn = 1 t m/s2 (= 103 N)

(= 10-5 N)

l h e kilogram-force (or kilopond) is that force which, when applied to a body having a mass of one kilogram, gives it the standard acceleration* due to gravity (Le. 9.806 65 m/s?). Thus,

28.3 In the foot-pound-second system the coherent force unit is the poundal (pdi). 1 kgf (or kp) == 9.806 65 kg iii/s2 (= 9.806 65 N)

1 pdl = 1 lb ft/s2 -- 0.453 592 37 x 0.3048 kg ni/s2

(= 0.138 255 N) (approximately) The corresponding technical force unit in general use in the UK and USA is the pound-force (lbf). It is

that force which, when applied to a body having a mass of one pound, gives it the standard acceleration* due to gravity. Thus,

9.806 65 0.3048 lb ft/s2 1 Ibf =

= 32.1740 pdl (approximately) (= 4.448 22 N)t

Furfher technical force units associated with the pound-force are the ounce-force (ozf), the U K ton-force

1 ozf = ~ I b f (= 0.278 014 N) 1 tonf = 2240 lbf (= 9964.02 N) 1 US ton-force = 2000 lbf (= 8896.44 N) 1 kip (USA only) = loo0 Ibf (= 4448.22 N)

(tonf) sind the US ton-force. in the USA a unit of loo0 lbf named the ‘ kip ’ is often used. 1

28.4 The kilogram-force (kgf), and the pound-force (Ibf) and its associated units, are both exactly defined in terms of the standard acceleration due to gravity. Because local acceleration due to gravity usually differs slightly from standard acceleration, it foliows that the forces exerted by gravity on bodies having a mass of 1 kg or 1 Ib are rarely exactly equal to 1 kgf or 1 lbf respectively, and account has to be taken of this when very high precision is required. See also section 29, Weight.

Interconyersion factors for the above units are given, or can be readily inferred, from Table 28.

* See 13.4. I- In exact ternis, 0.453 592 37 >: 9.806 65 N.

43


BSI BSa350: P A R T * l 74 m 1ib24bb9 O l L b l b L 3 m ~

BS 350 : Part 1 : 1974 Force

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29. Weight 29.1 Meaning of ' weight '. The term ' weight ' is commonly used either to denote mass or force, i.e. the mass of a body or the force of gravity acting upon it. It is used in the sense of mass in the UK Weights and Measures Act, 1963 and in common parlance; it is used in the sense of force by CGPM and in scientific and some technical work.

As weight values may be found quoted in either mass or force units both usages are accommodated in these conversion tables, To convert weight units when using weight in the mass sense use Tables 14a, 146 or 14c: to convert weight units when using weight as a force use Table 28. 29.2 Relatioitship between force of gravity and mass. The force of gravity (for example, expressed in newtons) is equal to the mass (in kilograms) multiplied by the local gravitational acceleration (in metres per second squared). For most practical purposes variations in local gravitational acceleration can be ignored and the standard value of 9.806 65 m/s2 is assumed (usually rounded to 9.81 m/s2).

It is the standard value of 9.806 65 m/s2 that is used in defining with precision the technical force units, the ki1ogram:force and the pound-force. 29.3 Accurate weight conversions, Conversions from one system of units to another on a mass to mass basis, or on a force to force basis, can be made with good accuracy by using the tables for sections 14 and 28 respectively, However, to obtain the accurate relationship of a mass to its associated gravitational force account has to be taken of the exact local value of the earth's gravitational field. The downward force on the mass is also affected by the bupyancy of any displaced atmosphere,

45


__- BSI BSs350: PARTxL 74 W LbZ4bb9 O L L b L b 3 7 W

~

BS 350 : Part I : 1974 Moment of force (torque)

30. Moment of force, or torque (force i: length) 30.1 The coherent SI unit of moment (of force) is the iiewtoii metre (N m), u derived uiiit. See the note below concerning the energy unit, which has a different physical significance. 303 A metric unit often used for moment, or torque, in continental countries is the kilogram-force metre (kgf m).

I ,

1 kgfm = 9.806 65 N m This unit is called the kilopond metre (kp m) in Germany.

poundal foot (pdl ft) (= 0.042 140 1 N m) pound-force foot (Ibf ft) (= 1.355 82 N m) pound-force inch (Ibf in) (= 0.112 985 N m) UKton-force foot (tonf ft) ounce-force inch (ozf in)

30.3 A selection of imperial units is:

(= 3037.03 N m) (= 7.061 55 x 10-3 N ni)

NOTE. The product newton x metre (N m) also expresses the SI unit for work done, or energy, a tinit having lhe special name joule (J), (see section 36, Energy). However, torque arid energy are diíïerent physical quantities; both are dimensionally force x length but in the former the directions of the force and length components are perpcndiciilar to each other while ii i the latter they are in line with each other.

With imperial units a distinction between torque units and energy units is made (by convention) by reversing the order of the units; e.g. the foot pound-force (ft Ibf) is an energy unit and the pound-force fooi (Ibf ft) a torque unit. There is no similar convention used or advisable with metric (including SI) units; it can be seen for exainple that rn-N (the reverse of N m) would easily be mistaken for mihewton.

Metric moment or torque units should be expressed 89 indicated in 30.1 and 30.2 above. It may be useful to point out that because both torque and energy are dimensionally the same (force x length) there is a Asanieitded

Jlrly1983 numerical correspondence between energy conversion tables and torque conversion tables.

P

46


BS 350 : Part 1 : 1974 Moment of force (torque)

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47


BSI BS*350: PART*L 74 m 3 6 2 4 b b î O L L b L b 5 O m

BS 350 : Part I : 1974 Force per unit length Pressure

31. Force per unit length * (forcdength) 31.1 The coherent SI unit is the newton per metre (N/m). 31.2 Another metric unit that may still be encountered is the dyne per centimetre (dyn/cm).

i dyn/cm = 10-3 N/m No interconversion tables are provided for force per unit length, The main reason for mentioning it here

is to show the distinction from torque.

32. Pressure (force/area) 32.1 The coherent SI unit of pressure is the newton per square metre, N/in2, for which the special name pascal (symbol Pa) was approved by the CGPM in 1971.

One pascal represents a very small pressure, and its multipies kilopascal (kPa) (or kN/m2) and megapascal (MPa) (or MN/m2) are therefore frequently used. 322 Arising from the historical evolution of the SI from the CGS system, some pressure units have a decimal relationship with the pascal. These are the dyne per square centimetre (dynlcm2) (sometimes called the barye), the pièze (pz), and the bar (bar)?. Only the last of these, with its multiples, persists in common use.

The dyne per square centimetre is also a very small pressure: i x 1 0 - 5 ~

(m/1W2 = 0.1 N/m2 = 0.1 Pa. 1 dyn/cm2 =

The pièze is the coherent pressure unit in the rnetre-tonne-second system, being equal to one sthène per

1 pz = 1 sn/m2 = 1 x 103 N/m2 = 1 kN/m2 = 1 kPa. The bar, 106 dyn/cmZ, is legally recognized in EEC countries and has a magnitude not far removed from

1 bar = 106 dyn/cm2 = 106 x 0.1 N/m2 = lo5 N/m2 = 105 Pa. One of its submultiples, the millibar, is widely used in the expression of barometric pressures.

square metre :

that of usual atmospheric pressure at sea level.

32.3 Also in common use on the Continent are the technical pressure units, the kilogram-force per square metre, and, in particular, the kilogram-force per square centimetre :

1 kgf/m2 = 9.806 65 N/m2 (exactly) 1 kgf/cm2 = 0.980 665 x 105 N/m2 (exactly) = 0.098 066 5 MPa In Germany and some other Continental countries the kilopond (kp) is used in place of the kilogram-force

These technical units have a simple relationship with conventional columns of water expressed in metric

= 9.806 65 Pa

(kgf), e.g. 1 kp/cm2 = 1 kgf/cmz.

terms (see 32.5). 32.4 Some imperial units in use, and that are expressed directly in terms of force per unit area, are:

poundal per square foot (pdl/ft2), the coherent unit in the foot-pound-second system

pound-force per square inch (lbf/in2) pound-force per square foot (lbf/ftz)

UKton-force per square foot (tonf/ft2) UKtoii-force per square inch (tonf/in2)

technical units

approx,

I 0.453 592 37 x (0.3048) N

(0.3048 m)2

0.453 592 37 x 9,806 65 N (0.3048 m)2

1 pdl/ft2 =

= 1.488 16 Pa (or N/m2)

- - 1 lbf/ft2

= 47,8803 Pa (or N/m2) approx.

* For example, surface tension. t The internationally recognized unit symbol for the bar is the same as the unit name. In meteorology, however, the commonly used symbol for the millibar is simply mb.

48


1 Ibf/inz = 144 lbf/ft2 = 6894.76 Pa (or N/m2) approx. 1 UKtonf/ftz = 2240 lbf/ft2 == 1.072 52 x 105 Pa (or N/m2) approx. 1 UKtonf/in2 = 2240 lbf/in2 = 1.54443 x lo7 Pa (orN/m2) approx. The pound-force per square inch (lbf/in2) is often known and shown by the abbreviation p.s.i., but,

although widely used in the UK and USA, this abbreviation is inconsistent with the internationally recognized symbology for units. In the USA, the expression ' ksi.' is often used to signify kips per square inch (Le. loo0 lbf/in2).

32.5 Liquid columns. Pressures are often measured in terms of the height of column of liquid, e.g. of mercury or of water. The pressure associated with a given height is dependent upon the density of the liquid and the local acceleration due to gravity. The following pressure units, based upon conventional density and gravity conditions, are internationally recognized:

the conventional miliimetre of mercury (symbol mmHg) ; the conventional inch of mercury (symbol inHg); the conventional millimetre of water (symbol mmH20); the conventional inch of water (symbol inH2O). The metre of water (mH2O) and foot of water (ftH20) are also used. 1 mmHaO = 0.001 m x lo00 kglm3 x 9.806 65 m/s2 = 9.806 65 N/m2 = 9.806 65 Pa (This is the pressure due to an ideal column of water of length 1 mm and of uniform density 1 g/cmJ,

1 mmHg =_ 13.5951 mmH20 = 13.5951 x 9.806 65 Pa = 133.322 Pa (approx.)* '

i inH20 = 25.4 mmH20 = 9.806 65 x 25.4 Pa = 249.089 Pa (approx.)

1 inHg = 25.4 mmHg = 9.806 65 x 13.5951 x 25.4 Pa = 3386.39 Pa (approx,)

I ftH2O == 304.8 mmH2O = 304.8 x 9.806 65 Pa = 2989.07 Pa (approx.)

Another pressure unit in common use known as the torr is equal, within one part in 7 million, to the conventional rniliinietre of mercury (mmHg). It is, however, precisely defined in terms of the pascal as follows :

when under the standard condition g, = 9.806 65 m/s2)

101 325.0 760 Pa I torr =

-- 133.322 Pa (approx.) Because of its size, the pascal is well-suited to vacuum technology. However, in addition to the millibar

and torr and their submultiples, the term ' micron ' meaning micrometre of mercury (pmHg), is still common in this field. The symbol pmHg is sometimes (incorrectly) contracted to p.

Following from its definition, the conventional millimetre of water is exactly equal to the kilogram-force per square metre:

1 mmH2O = 1 kgf/m2 (or kp/m2) Similarly, 10 mH20 = 1 kgf/cm2 (or kp/cm2).

32.6 Atmospheres. Attention is called to the significance of the following terms and symbols: Standard atmosphere (atm). This is an internationally esfablished reference for pressure of 101 325 Pa,

being equal to 760 mmHg within one part in 7 million. It should not be regarded or used as a unit, but it is of great importance and in widespread use as a reference.

The technical atmosphere (at). This unit, which is used on the Continent, is equal to the kilogram-force per square centimetre, or kilopond per square centimetre:

1 at = 1 kgf/cm2 (or kp/cm2) = 98 066.5 Pa

32.7 ' Absolute ' and ' gauge '. All the pressure units mentioned in 32.1 to 32.6 may be used to state the magnitude of an absolute pressure or of a pressure difference, and misunderstandings in interpretation and conversion may arise if the quantity concerned is not clearly expressed.

It has been internationally recommended that pressure units themselves should not be modified to indicate whether the pressure value is ' absolute ' (i.e. with zero pressure as the datum) or ' gauge ' (i.e. with atmospheric pressure as the datum). * For detailed information on barometer conventions see BS 2520.

49


~

BsI BS*350: PART*L 74 Lb24bbq OLLb1ib7 4

BS 350 : Part 1 : 1974 Pressure

Both in the UK and USA it was commoii practice to use the abbreviation p.s.i. to indicate Ibf/in2, and Lo differentiate between gauge and absolute pressures by adding the further letters ' g ' and ' a ' to make ' p.s,i.g.' and ' p.s.i.a.' respectively. A similar situation existed in German practice, where the symbol for the technical atmosphere (at) was modified to atü or ata to indicate the expression of ' gauge ' (über) or ' absolute ' pressure respectively*. Of these, only ' at ' was an internationally recognized unit symbol; furthermore the modiñcations did not change the units of measurement, but were in fact an indication of the quantity being expressed.

From the recommendation in the second paragraph it follows that, if the context leaves any doubt as to which quantity is meant, the word ' pressure' should be qualified appropriately:

e.g. ' at a gauge pressure of 12.5 bar ' or ' at a gauge pressure of 1.25 MPa ' or ' at an absolute pressure of 2.34 bar ' or ' at an absolute pressure of 234 kPa '. Absolute pressures are always positive, but gauge pressures are shown as negative when indicating a

It is common practice in the power and process industries to refer to ' vacuum ' values, e.g. ' I mmHg vacuum ' represents a gauge pressure of -1 mmHg, and

pressure less than the datum pressure.

' one per cent of vacuum ' represents a gauge pressure of minus one per cent of the datum atmosphere in use.

* With the atü, the datum is an absolute pressure of 1 at.

Interconversion factors for the above units are given, or can be deduced from, Tables 320, 32b and 32c. See also section 33, Stress.

50


BS 350 : Part I : 1974 Pressure

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BS 350 : Pressure

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BS 350 : Part 1 : 1974 Pressure

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BSI BS*350: P A R T * L 74 IPI Lb24bbï O L L b L 7 1 b R

BS 350 : Part I : 1974 Stress Viscosity (dynamic) 33. Stress ( fordarea) Though it is a different physical quantity, stress is iiaturally treated with pressure, since it is also force divided by area. Many, but not ali, of the iiiiits mentioned in connection with pressure are used for stress, so the conversion factors in Tables 320, 326 and 32c will be found useful.

The coherent SI unit of stress is again the pascal (Pa), Le. the newton per square metre (N/rna). Technical units that have been widely used for stresses in metals and some other materials are the kilogram-

force per square millimetre (kgf/mm2), pound-force per square inch (Ibf/in2) and U Kton-force per square inch (UKtonf/in2)*. In the change to SI, a practical unit of similar size to the kgf/mm? was sought, the first proposal being the hectobar (hbar), which came into some use. However, the hbar is being abandoned in favour of the N/mm2, which can be otherwise stated as MN/m2 or MPa:

1 N/mmz = 1 MN/m? = 1 MPa 1 kgf/mm2 = 9.80665 N/mm2 = 9.80665 MPa 1 hbar = 100 bar = 102 x 105 N/ni? -= 10 NIPa

NOTE. Intercoii\ersion factors for these and other units used for strcsscs are givcn o r ciiii be dcditccd ïroiii Tables 31u, 3 3 and 32c. See also section 32, Pressure.

34. Vipcosity, dynamic (stress/velocity gradient) 34.1 The coherent SI unit of dynamic viscosity is the pascal second (Pa s), which iilay also be expressed a s the newton second per square metre (N s/m2), or as the kilogram per metre second (kg/(rn s)).

This unit has also been called the poiseuille (Pi) iii France. (It should be noted that this is iiot the same as the poise (P), described in 34.2). 34.2 The poise (P) is the8orrespondiiig CGS unit.

1 P = 1 dyn s/cm2 = 10-1 N s/m2 = 10-1 Pa s. The commonIy used submultiple is the centipoise (cP). 1 CP = 10-2 P = 10-3 Pa s.

34.3 Other metric and imperial units that have been used for dynamic viscosity are: kilogram-force second per square metre poundal second per square foot pound-force second per square foot pound force hour per square foot pound-force second per square inch? pound per foot hour

(kgf slni?) = pound per foot second, Ib/(ft s> (pdl s/ftz) = slug per foot second, slug/(ft s) (lbf s/ft2) = slug hour per foot second squared, slug ii/(ft sz) (lbf h/ft2)

(lbf s/in2) (lb/ft li)

1 kgf s/m2 = 9.806 65 Pa s 1 pdl s/ft2 = 1.488 16 Pa s 1 Ibf s/ft2 = 47.8803 Pa s i Ibf h/ft2 = 1.723 69 x iOS Pa s

TI lbf s/in2 = 6894.76 Pa s 1 Ib/ft h = 4.133 79 x 10-4 kg/(m s) = 4.133 79 x 10-4 Pa s

NOTE. For reference to frequently used but empirical uiiits of viscc>s¡ty, such i ls the Redwood sccoiid. sw scctioii 33, Viscosity, kinematic.

Interconversion factors for most of these units are given in Table 34.

* Iii tlie USA, tlie expressioii ' k.s.i.' is ofteii uscd to S¡gii¡fY kips pet square inch (¡.c. 1000 Ibf/iii:ì. t Sonietinies called the ' reyn '.

54


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BS 350 : Part I : 1974 Viscosity (dynamic)

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BSI BS*350: PART*:L 74 Eb24669 0lLbL73 T I

BS 350 : Part 1 : 1974 Viscosity (kinematic)

35. Viscosity, kinematic (length squared/time)

35.1 The coherent SI unit of kinematic viscosity (which is dynamic viscosity divided by density) is the metre squared per second (m2/s). 35.2 The corresponding CGS unit is the stokes (St).

1 St = 1 cm2/s = 10-4 m2/s The common submultiple is the centistokes (cSt).

1 cSt = 10-2 St = 10-6 m2/s (= 1 rnmys) 35.3 Another metric unit sometimes used is the metre squared per hour (m2/h).

1 m2/h = 2.777 78 x 10-4 m2/s 35.4 A selection of imperial units is:

inch squared per second in2/s foot squared per second ft2/s inch squared per hour in2/h foot squared per hour ft2/h

1 in2/s = 6.4516 x 10-4 m2/s 1 ft2/s = 9.290 30 X 10-2 d / s 1 in2/h = 1.792 11 x 10-7 m2/s 1 ftZ/h = 2.580 64 x 10-5 m2/s

35.5 The units referred to in 35.1 to 35.4 are absolute units with physical dimensions, as distinct from values on frequently used but empirical scales such as Redwood No. 1, Saybolt Universal, and Engler degrees. For tables from which viscosity values in these empirical scales may be converted to centistokes see ESDU* Item No. 68036, sponsored by the Institution of Mechanical Engineers.

Interconversion factors for the units in 35.1 to 35.4 are given in Table 35. Note that this table may be used for the conversion of values of thermal diffusivity, which also has the dimensions of length squared/time.

* ESDU Item No. 68036 ' Introductory m,emorandum on the viscosity of liquids and the classification of lubricating oils ' obtainable from:

Engineering Sciences Data Unit, 251-259 Regent Street, London W1R 7AD.

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BSI BS*350: PART*L 74 W 1624669 OLLbL75 3

BS 350 : Part I : 1974 Energy

36. Energy (work, heat, etc.)

36.1 The coherent SI unit for the expression of all.for./ris of energy is the joule (symbol J).

in different ways, e.g.: Just as energy arises in many ways, the connection between the joule and other SI unils may be iiidicated

I J = 1 N m (force x distance, newton metre) = I W s (electrical energy, watt second) = 1 Pa m3 (pressure x volume, pascal cubic metre)

(This unit was, prior to the Si, known as the absolute joule, but it is now simply the joule (J). The ' international ' joule, which became obsolete in 1948, was approximately equal to 1.OOO 19 J.) 36.2 Arising from the historical development of the SI from the CGS system, the unit of energy in the CGS system (the erg) is decimally related to the joule.

1 erg = 1 dyn cm = 1 x lO-sN x 0.01 m = 10-7 N m = 10-7 J

36.3 A unit in extensive use for the expression of electrical energy is the kilowatt hour (kW li).

I kW h = 1 x IO00 x W x 36009 = 3.6 X 106 W s = 3.6 MJ

36.4 Two other metric units used for the expression of energy are the kilogram-force iiietrc* ( k f g ni) and the litre atmosphere.

1 kgf m = 9.806 65 N m = 9.806 65 J 1 litre atmosphere = 1 dm3 x 101 325 Pa 7 - 101.325 Pa in3

= 101.325 J (The litre used here is equal to i decimefre cubed (see 4.3), and the atmosphere used is the standard atinos- phere (see 32.Q.) 36.5 Some corresponding imperial units used for the statement of energy are the foot poundal (ft pdl), the foot pound-force (ft Ibf) and the horsepower hour (lip li).

1 ft pdl = I x 0.3048 m x 0.453 592 37 x 0.3048 N (see 31.3) = 0.042 140 1 J (approx.)

I ft Ibf L- 1 x 0.3048 m x 0.453 592 37 :.: 9.806 65 N (see 31.3) = 1.355 82 J (approx.)

1 lip h = 550 ft lbf/s x 3600 s (see 37.3)

= 2.684 52 x 106 J (approx.) = 1.98 x 106 ft lbf

36.6 Heat units. Heat is one of the forms of energy and, as stated abovc, tlic Si unit for all forms is the joule. The following heat units originally arose from the concept of the heat required to warm unit mass of water through unit temperature, but some of these are now precisely defined in terms of the joule:

the various calories (originally relating to the gram of water aiid the degree Celsius); the various British thermal units (originally relatiiig to the pound of water and degree Fahrenheit) ; and the various Centigrade heat units (based on the pound of water and the degree Celsius). The specific heat capacity of water changes with temperature and a number of different calories, British

thermal units, and Centigrade heat units came into use according to their memis of definiiioii. Three of tlie calories are still in some practical use and in precise work need to be separately identified.

These are the International Table calorie (cailT), the thermochemical calorie (cal,,,) and tlie 15 "C calorie (cal 1 5) described below :

I calIT = 4.1868 J (as defined at the Fifth International Conference on Properties of Steain, London 1956). I cal,,, = 4.1840 J (a ' defined ' calorie). I cal 15 = 4.1855 J (approx.) (This is defined as the amount of heat required to \varni I g of air-freewater

îrom 14.5 "C to 15.5 "C at a constant pressure of 1 atm. The joule equivalent shown above wíis adopted by the CIPM i n 1950 as being the most accurate value which could then be deduced from experinien t.)

Associated with the cal15 are the thermie (tli), also sometinies describcd as the ' tonne-calorie ' and the

1 thermie = 106 cal15 = 4.1855 MJ (approx.) 1 frigorie = - IO3 call5 = -4.1855 kJ (approx.)

4s0,tte,,ded ' t r '~ 'g83

frigorie, used in connection with tlie extraction of heat.

* Known as the kilopond metre (kp m) in Germany.

58


e

BS 350 : Part i : 1974 Energy

The ' calorie ' commonly referred to in nutritional science is in fact a kilocalorie, which is sometimes called a ' kilogramcaloric ' or ' large caloric '. In this standard, if the symbol cal is used without qualification, it refers to the International Table calorie (callT). (The dietitians calorie is based on the call5.)

The most important British thermal unit (Btu), aiid the one used throughout this standard, is the one corresponding to the International Table calorie and is defined by the equation:

I Btu/lb = 2.326 J/g thus 1 Btu = 2.326 x 453.592 37 J = 1055.06 I (approx.) Among other British thermal units formerly in use but now obsolescent are: the ' 60 O F British thermal unit ' (heat required to warm 1 lb of water from 60 O F to 61 O F ) . 1 BtU60/61 = 1054.5 J (apprOX.) the ' mean British thermal unit ' (i / i80 of tlie heat required to warm i Ib of liquid water from 32 "F

I Btu,,," -= 1055.8 3 (approx.) The British thermal unit used for most purposes by the British Gas industry relates to the 15 "C caloric

to 212 O F ) .

and is equal to:

- 1054.73 J (approx.) 4.1855 4.1868

2.326 X 453.592 37 J x - - Associated with the Btu is the therm, used as an energy unit by the Gas Industry. 1 therm = 100 o00 Blu = 105.5 MJ (approx.) The ' Centigrade heat unit (C.H.U.), based on the Ib of water and tlie OC, is still sometinies used. I C.H.U. = 1.8 Btu (but to each British thermal unit there corresponds a Centigrade heat mi t ) 1 C.H.U.,,,,, = 1.8 Btu,,,ciin =- 1900.4 J (approx.)

For interconversion factors for most of the above units see Tables 36a and 36U.

59 COPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling ServicesCOPYRIGHT British Standards Institute on ERC Specs and StandardsLicensed by Information Handling Services

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BS 350 : Part 1 : 1974 Power

37. Power (energy/time) 37.1 The coherent SI unit for all forms of power, including heat flow rate, is the watt (symbol W), which is equal to the joule per second.

1 W = I J/s The kilowatt (kW) is a commonly-used multiple of the watt.

37.2 Two metric technical units of power are the kilogram-force metre per second (kgf m/s) and the metric horsepower*.

APamndeà 1 kgf m/s = 9.806 65 31s = 9.806 65 w 1 metric horsepower = 75 kgf m/s = 735.499 W

July 198.3

37.3 Similar technical units in the imperial system are the foot pound-force per second (ft Ibf/s) and the horsepower (hp).

1 ft lbf/s = 1.355 82 J/s (see 36.5) = 1.355 82 W 1 hp = 550 ft lbf/S = 745.700 W

37.4 The following is a selection of heat flow units shown in terms of the watt: calorie per second 1 cal/s = 4.1868 W

British thermal unit per hour ' ton of refrigeration ' = 12 o00 Btu/h = 3.516 85 kW

kilrocalorie per hour 1 kcal/h = 1.163 W }see 36.6 1 Btu/h = 0.293 071 W

For interconversion factors for most of the above units see Table 37.

The metric horsepower goes under the name ' cheval vapeur * in Francs and sometimes the Symbols ch or CV arc used. In Germany it is called the ' Pïerdeatgrke * (symbol PS).

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63


BS 350 : Part I : 1974 Tem perat u re

38. Temperature, including temperature difference or interval 38.1 The SI unit of temperature is the kelvin (K). It is one of the base units of the SI aiid is defined as a specified fraction (&-J of the thermodynamic temperature of the triple point* of water. The kelvin is used for the expression of thermodynamic temperature, for which the datum is absolute zero: i t can also be used for the expression of any temperature difference or temperature interval. 38.2 The temperature unit in most practical use in metric countries, and recognized for use in conjunction with the SI, is the degree Celsius ( O C ) , The now incorrect terni ‘ Centigrade ’ is still in widespread use for

. ~ \ U I I I V I I M Celsius. The zero datum for Celsius temperature (O ‘C) is now exactly defined by the thermodynamic temperature 273.15 K; formerly it was defined by the melting point of ice at 1 atm, The units of temperature Iidy 1983

difference, one degree Celsius and one kelvin, are exactly equal, by definition. In this sense

and any temperature difference therefore has the same numerical value when expressed in OC as it has when expressed in K.

For formulae showing the interrelationships between Celsius temperatures and thermodynamic temperatures expressed in kelvins, and some other temperatures mentioned below, see Table 38. 38.3 Traditional in practical use in the UK and USA is Fahrenheit temperature, now being rapidly displaced by Celsius. The Fahrenheit scale is not formally defined, but it is generally recognized that:

i ° C = 1 K

32 O F is the ice point 212 O F is the boiling point of water at 1 atm

and that the unit of temperature difference one degree Fahrenheit ( I O F ) is equal to five ninths of the unit of temperature difference the degree Celsius (1 OC). In this sense

1 ° F = (:OC) = (:IC)

For formulae giving the interrelationship between Fahrenheit, Celsius, and other temperatures see Table 38. 38.4 For thermodynamic temperatures, the degree Rankine (OR) is still occasionally used. The unit interval of the degree Rankine is equal to 1 O F , a thermodynamic temperature of O O R being absolute zero. See Table 38. 38.5 In the last edition of this standard, for temperature interval the letters ‘ deg ’ were recommended, instead of the degree sign ( O ) which was reserved for temperature. In 1967-68, the 13th CGPM considered the arguments for and against this practice and decided to recommend that the use of ‘ deg ’ should be discontinued. 38.6 For the purpose of practical measurements the CIPM adopted i n 1968 the ‘ International Practical Temperature Scale of 1968 ’, IPTS - 68, based on reproducible fixed points and interpolation instruments and procedures. The IPTS - 68 has been designed so that the International Practical Kelvin and Celsius temperatures closely approximate the Kelvin and Celsius temperatures described in 38.1 and 38.2. The IPTS - 68 is defined only from a thermodynamic temperature of 13.81 K upwards.

* The temperature at the triple point of water, (where water, ice, and water vnpour are in equilibrium) is very slightly removed from the temperature of the melting point of ice at atmospheric pressure (the ice point).

64


BS 350 : Part I : 1974 Temperature

Specific energy

Table 38. Equivalent values on four temperature scales For the bdme temperature, if [T] K, [0] OC, [t] O F and [r] O R represent that temperature on the Kelvin, Celsius, Fahrenheit and Rankine scales respectively, then the formulae relating the pure numbers [TI, [O], [t] and [r] are as shown below.

(kelvins) I % UI>lL~lll l l c i

5 5 Jeli I W / T / = / e / + 273.15 = - ( I t / + 459.67) = 9 Ir] 9

(degrees Celsius) í / r ] - 491.67) 5 - 5 9

/ e / = / T I - 273.15 = ( i t ] - 32) - -

9 9 = Ir] - 459.67 (degrees Fahrenheit) / I / = / T / - 459.67 = I, / e / + 32

- - [ e / + 491.67 = / t / + 459.67 - 5 (degrees Rankine)

NOTE. Temperafure difference. For the same temperature difference: 5 9

(temperature difference in "C or K) = - (temperature difference in OF or OR).

39. Specific energy [(energy or heat)/massl 39.1 There are several different terms for energy per unit mass which are used in different contexts, e.g.

specific enthalpy specific latent heat calorific value, mass basis The SI unit for all such quantities is the joule per kilogram (J/kg).

kilocalorie per kilogram (kcal/kg) (see 36.6) kilogram-force metre per kilogram (kgf m/kg) 1 kcal,,/kg = 4186.8 J/kg 1 kcalth/kg = 4184 J/kg 1 kcalis/kg = 4185.5 J/kg (approx.) I kgf m/kg = 9.806 65 J/kg

39.3 Corresponding imperial units are: British thermal unit per pound foot pound-force per pound 1 Btu/lb = 2326 J/kg 1 ft lbf/lb = 2.989 07 J/kg (approx.)

For interconversion factors see Table 39.

39.2 Other units sometimes used in metric countries are:

(Btu/lb) (ft lbf/lb)

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BS 350 : Part 1 : 1974 Heat content, volume basis

40. Heat content, volume basis (heat/volume)

40.1 The SI unit for this quantity, which is mainly used in connection with the combustion of gaseous or liquid fuels, is the joule per cubic metre (J/m3). For most practical purposes either the kJ/m3 or MJ/m3 are suitable multiples. 40.2 Units that have been in common use in metric countries are:

e.g. calorific value, volume basis

kilocalorie per cubic metre (kcallmj) (see 36.6 for the various calories) thermie per litre (th/Utre) 1 kcal,,[mJ = 4186.8 J/niJ 1 kcal,,/m3 = 4184 J/m3 1 kcal&3 = 4185.5 J/m3 1 thermie/litre = 4185.5 x 106 J/m3 (see 4.3 for litre)

40.3 Corresponding imperial units are: British thermal unit per cubic foot (Btu/ft3) therm per UK galloii (therni/UKgal) I Btu/ft3 1 therm/UKgal = 2,320 80 x 1010 J/m3

= 37 258.9 J/m3

40.4 In the above and in Table 4ûu it is assumed that, where guses are concerned, the volumes involved in the conversion have the same reference conditions of temperature, pressure and humidity. For some conversions of calorific value (volume basis), when the reference conditions are different, see Tables 406 and 4oc.

67


BS 350 : Part I : 1974 Heat content, volume basis

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BS 350 : Part 1 : i974

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Heat content, volume basis Specific heat capacity Table 40c. Conversion factors used by the UK Gas Industry The following information and conversion factors are extracted from the booklet ' SI Units and conversion factors for use in the British Gas Industry ' issued by the Gas Council and Society of British Gas Industries, May 1972 edition.

Dry Sat

1 0.9832 I .O1 7 1

0.037 3 1 0.036 69 0.037 97 0,037 34

0.037 30 0.036 67 0.037 96 0.037 32

~~ ~~~~ ~~

The conversion factor for converting from British thermal units per cubic foot (measured at 60 OF, 30 inches Hg (@ 60 OF 53 ON) and saturated with water) to megajoules per standard cubic metre (measured at 15 "C 1013.25 mbar and dry) is:

1 Btu/ftJ = 0.037 96 MJ/m3 Other conversion factors for various conditions are given in the table below. Whereas two bases for the British thermal unit are included, for practical purposes there is no sigiiífi-

cant difference between them. In the gas industry the British thermal unit is based on the 15 O calorie.

1 MJ/mJ = 26.34 Btu/ftJ

Dry

26.80 27.26

1 1.018

0.9997 1.017

MJ/m-' 15 OC 1013.25 mbar

26.33 26.78

Bt u/ ft 3 M) O F 30 inches Hg (International calorie basis)

26.81 26.34 27.27 26.79

Btu/ft3 60 "F 30 inches Hg 115 O calorie basis)

0.9826 1

0.9823 0.9997

- Dry Sat

1.ûOû 0.9829

-- I 1.018

Dry Sat

- Dry Sat -

MJ/mJ 15 OC

I Btu/R3 60 OF, 30 inches

NOTE. (This tiote is for users of BS 350 and is not part of the GC/SBGI booklet.) Attention is called to the foilowing differences in the reference bases of Tables 4Oh and 4Oc. (1) In Table 4ûb the only British thermal unit used is the one corresponding to the International Table calorie (sec 36.6).

In Table 4oc this Btu is indicated by the parentheses (International calorie basis) or (IT calorie), and factors relating to a Btu based on the 15 "C calorie are stated in the preamble above the table and included in the table.

(2) The pressure ' 30 inches Hg ' as shown and under the conditions stated in Table 4Oc is given as being eqiial to 1013.7405 mbar. Thc pressure 30 inHg shown in Table 406 (and as defined at 32.5) is, approximately, 1015.9166 mbar.

41. Specific heat capacity" [heat/(mass x temperature interval)] $1.1 The SI unit of specific heat capacity is the joule per kilogram kelvin (J/(kg K)). 41.2 The degree Celsius is often used in the expression of the above unit:

I J/(kg OC) = I J/(kg K) and a similar remark applies wherever kelvin or K is mentioned in the remainder of section 41. 41.3 Other metric units are:

kilocalorie per kilogram kelvin (kcal/(kg K)) (See 38.6 for the various calories.) kilogram-force metre per kilogram kelvin (kgf m/(kg K) ) 1 kcal,,/(kg K) = 4186.8 J/(kg K) 1 kcal,,/(kg K) = 4184 J/(kg K) I kcallS/(kg K) = 4185.5 J/(kg K) 1 kgf m/(kg K) = 9.806 65 J/(kg K)

41.4 Corresponding imperial units are: British thermal unit per pound degree Fahrenheit (Btu/(lb O F ) )

foot pound-force per pound degree Fahrenheit (ft Ibf/(lb OF)) I Btii/(lb OF) 1 ft lbf/(lb OF) = 5.380 32 J/(kg K)

= 4186.8 J/(kg K)

For inteaconversion factors for the above units see l'able 41. <' The older and simpler t e m ' specific heat ' referred to heat capacities, usually on a mass basis but sometimes on a volume basis. Jt is now preferred to reserve for ' specific ' tlie meaning ' per unit mass '.

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BS 350 : Part i : 1974 Specific heat capacity

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BS 350 : Part I : 1974 Specific entropy Heat capacity, volume basis

42. Specific entropy [heat/(mass x thermodynamic temperature)] Table 41 may also be used for the conversion of values of specific entropy, expressed in jouies per kilogram, kelvin, J/(kg K), in kilocalories per kilogram kelvin, kcal/(kg K), or in British thermal units per pound degree Rankine, Btu/(lb OR).

43. Heat capacity, volume bask * [heat/(volume x temperature interval) I 43.1 The SI unit of heat capacity, volume basis, is the joule per cubic metre kelvin (J/(mJ K)). 43.2 The degree Celsius is often used in the expression of the above unit:

I J/(m3 O C ) = 1 J/(m3 K) and a similar remark applies wherever kelvin or K is mentioned in section 43. 43.3 Other metric units are:

kilocalorie per cubic metre kelvin (kcall(m3 K)) (see 36.6 for the various calories). 4 kcalIT/(m3 K) = 4186.8 J/(m3 K) 1 kcal,,/(m3 K) = 4184 J/(m3 K) 1 kcalls/(m3 K) = 4185.5 J/(m3 K)

43.4 The corresponding imperial unit is: British thermal unit per cubic foot degree Fahrenheit (Btul(ft3 OF)) 1 Btu/(ft3 O F ) = 67 066.1 J/(m3 K)

For interconversion factors for the above units see Table 43. In Table 43 and in the above conversion factors it is assumed that, for gases, the volumes involved in the conversions are measured under the same conditions of temperature, pressure and humidity. * This is sometimes known as ' specific heat, volume basis ' but see footnote fo section 41.

Table 43. Heat capacity, volume basis Exact values are printed in bold type.

I I I I

1 joule per cubic metre - kelvin? -

joule per cubic metre kelvin?

JKm3 K)

1

kilocalorie$ per cubic metre kelvin

kC&~/(ni~ K)

0.238 846 x 10 -3

thermochemical kilocalorie per cubic metre kelvin k d d ( m 3 K)

0.239 006 x 10 -3

15 "C kilocalorie per cubic metre kelvin

kwhd(m3 K)

0.238 920 X lO'-J

4186.8 I 1 1 kilocalorie$ per cubic

metre kelvin kcallT/(rn3 K)

1.ooO 67 l.OO0 31

1 thermochemical kilocalorie per cubic metre kelvin = kcal,,,/(mJ K)

1 15 "C kilocalorie per - cubic metre kelvin - kCaldm3 K)

1 British thermal unit per cubic foot degree Fahrenheit - Btu/(fts OF)

-

1 0.999 642 4184 0.999 331

4185.5 0.999 690 1.O00 36 1

67 066.1 16.0185 16.0292 16.0234

British thermal unit per cubic foot degree Fahrenheit Bhi/(ftj "F)

14.910 7 x 10 -6

0.062 428 O

,-

0.062 386 2

-

0.062 408 6

1

t Wherever the kelvin occurs in this table it may be replaced by the degree Celsius ( "C), e.g. J/(m3 K) is often show as J/(rn3 OC). $ This is the International Table kilocaforie. For a description of the three calories mentioned see 36.6.

NOTE. In this table it is assumed that, for gases, the volumes involved in the conversions are measured under the same conditions of temperature, pressure and humidity.

. 72


BS 350 : Part I : 1974 Heat flux density

4 4 Heat flux density (heat/(area x time)) 44.1 The SI unit for this quantity, which is sometimes known as intensity of heat flow rate and commonly appears, for example, in calculations of heat losses from surfaces, is the watt per square metre (W/m2). 44.2 Other metric units are:

calorie per square centimetre second (cal/(cm2 s)) (see 36.6 for the various calories) kilocalorie per square metre hour (kcal/(m2 h)) 1 calIT/(cm2 s) = 41 868 W/m2 1 kcaliT/(mz h) = 1.163 W/m2

British thermal unit per square foot hour (Btul(ft2 h)) watt per square inch (Wlin2) 1 Btul(ft2 h) = 3.154 59 W/m2 1 WIin2 = 1550.00 W/m2

44.3 Corresponding units in the imperial system are:

For conversion factors for the above see TabIe 44.

Table 44. Heat flux density, intensity of heat flow rate (ag. heat loss from surfaces) Exact figures are printed in bold type.

W/m2

1 watt per square metre = 1 W/m*

1 watt per square inch = 1550.00 W/in2

1 calorie* per square centimetre second = 41868 W1iT/(cm2 s)

1 kilocalorie* per square metre hour = 1.163 kCa1,T/(m2 h) -

1 British thermal unit per square foot hour = 3.154 59 Btu/(ft2 h)

*This refers to the International Table calorie.

0.238 846 x 10 -4

3.702 12 x 10 -2

1 I l 27.01 16

I

ir other calories see 36.6.

0.859 845 I 0.316 998

1332.76 491.348

%o00 13 272. i

1 0.368 669

2.71246 1

73


BS 350 : Part I : 1974 Thermal conductance

45. Thermal conductance (heat transfer coefficient) [heat/(area x time x temperature difference)] or [power/(area x temperature difference)]* 45.1 The SI unit is the watt per square metre kelvin [W/(m2 K)] 45.2 The degree Celsius ( O C ) is often used in the expression of the above unit:

and a similar remark applies wherever kelvin or K is mentioned in sectioii 4 5 45.3 Other metric units are:

1 W/(m2 OC) = 1 W/(m2 K)

calorie per square centimetre second kelvin [cal/(cm 2 s K)] kilocalorie per square metre hour kelvin [kcal/(rna li K)]

1 caI/(crn2 s IS) = 41 868 W/(m2 K) 1 kcal/(m2 h K) = 1.163 W/(nG K)

45.4 The imperial unit in common use is: British thermal unit per square foot hour degree Fahrenheit [Btu/(ft2 h “F)]

I dtu/(ft2 li O F ) = 5.678 26 W/(m2 K)

(The conversion factors given below refer to the Iiiternational Table calorie, sce 38.6 for other calories.)


Table 45. Thermal conductance Exact values are printed in bold type.

\V/(mZ K)P cal$/(cmz s K) kcai$/(mz h K) - 1 watt per square

metre kelvin? = 1 0.238 846 x IO -4 0.859 845 W/(m2 K)

1 calorie$ per square centimetre secoiid kelvin = 41 868 1 36 O00 cal/(c& s K)

i kilocalorie$ per square metre hour kelvin = 1.163 2.777 78 x 10-5 1 kcal/(mz h K)

1 British thermal unit per square foot hour degree Fahrenheit = 5.678 26 1.356 23 x IO -4 4.882 43 Btul(ft2 h O F )

0.176 110

7373.38

0.204 816

1

O

e

* Also corresponds to (heat flux density/temperature difference).

.I_ Wherever the kclvin occurs in this table it may be replaced by tho degree Celsius: e.p. W / ( d K) is ofteii sliowii as W/(nii- OC)

3 This refers to the International Table calorie. For other calories sce 36.6.

74


BS 350 : Part 1 : 1974 Thermal conductivity

0.577 789

46. Thermal conductivity [heat x length/(area x time x temperature difference)] 46.1 The SI unit is the watt per metre kelvin [W/(m K)] 46.2 The degree Celsius ( O C ) is often used in the expression of the above unit:

1 W/(m O C ) == 1 W/(m K) and a similar remark applies wherever kelvin or K is mentioned in section 46. 46.3 Other metric units are:

calorie per centimetre second kelvin kilocalorie per metre hour kelvin

I cal/(cm s K) = 418.68 W/(m K) 1 kcal/(m h K) = 1.163 W/(m K)

[cai/(cni s K)] [kcaI/(m h K)]

(The conversion factors given below refer to the Internationai Table calorie. See 36.6 for other caiurics),

46.4 Two imperial units in common use are: British thermal unit per foot hour degree Fahrenheit [Btu/(ft 11 "F)] British tliernial unit inch per square foot hour degree Fahrenheit 1 Btu/(ft h O F )

I Rtii in/(ftz li 'F) -- 0.144 228 W/(m K)

[Btu in/(ftz h O F ) ]

= 1.730 73 W/(in K)

6.933 47

For interconversion factors for the above units see l'able 46.

1.488 16

0.124 014

~

Table 46. Thermal conductivity

1 caloriet per centimetre second kelvin = cal/(cm s K)

Exact figures are printed in bold type.

kcal/(m h K)

' 418.68 1

l I- -I

1 kilocalorie* per metre hour kelvin = kcal/(m h K)

I 0.238 846x 10-2 =I I watt per metre kelvin* W/(m K)

1.163

1 British thermal unit per foot hour degree Fahrenheit= Btu/(ft h°F)

1.730 73 4.133 79x 10-3

2.777 78 x 10 -3

1 British thermal unit inch per square foot hour degree = Fahrenheit Btu in/(ft2 h O F )

0.859 845

0.144 228 3.444 82x 10-4

360

1

Bíu/(ft h 'F) Btu in/(ft2 h 'J!) 7 2902.91 241.909

-

1 I 1 2

0.083 333 3 1 I * Wherever the kelvin occurs in this table it maybe replaced by the degree Celsius (Oc) e.g. W/(m K) is often shown as W/(m O C ) . P This refers to the International Table caloric. For other calories see 36.6.

75


BSI BS*350: P A R T * & 74 I Lb24bbï OlilbL93 5 ~~

BS 350 : Part i : 1974 The r ma I resist ¡vi ty

47. Thermal resistivity [area x time x temperature difference/(heat x length)] The SI unit of thermal resistivity (the inverse of thermal conductivity) is the metre kelvin per watt (m K/W).

Interconversion factors between tue above and some other units are given in Table 47. Similar remarks concerning the use of the degree Celsius and the other calories apply as in section 46 and Table 46.

Table 47. Thermal resistivity Exact figures are printed in bold type.

I mK/W I cmsK/caì*

1 mK/W = 1 418.68

1 cm s K/cal* = 0.238 846 X 10-2 1

360

241.909

1 ft2 h OF/(Btu in) = 6.933 47 1 2902.91

I I It2 h 'F/(Btu in) i 0.144 228

m h K/kcal* it h 'F/Bîu

1.163 1.730 73 ~~~~~~ ~~

2.777 78 x 10 -3 I 4.133 79 x 10 -3 1 3.444 82 x 10-4

1 1.488 16 0.124 014

0.671 969 1 0.083 333 3

8,063 63 12 1

-

* This refers to the International Table calorie. For other calories see 36.6.

NOTE. For thermal conductivity, see Table 46, the notes to which also apply here.

76


8 1 watt per cubic metre

1 calorie* per cubic

W/m3

centimetre second = cal/(cm3 s)

1 kilocalorie* per cubic metre hour = kcal/(m3 h)

1 British thermal unit per cubic foot hour = Btul(ft3 h)

*

watt per cubic metre W/m3

= 1

4.1868~106

1.163

10.3497

BSI ~~ BS*350: ~~~~ P A R T * l ~~ 74 ~ _________ ~ œ 3624669 OlLbLSY 7 œ __ -~ ~-

BS 35Ö:Part I : 1974 Heat release rate

Thermal diffusivit.y 48. Heat release rate (ems. as used in connection with furnaces) [heat/(volume x time)], or (power/volume) 48.1 The SI unit for this quantity is the watt per cubic metre (W/m3). 48.2 Other metric units are:

calorie per cubic centimetre second kilocalorie per cubic metre hour The conversion factors given below refer to the International Table calorie. (See 36.6 for other calories). 1 cal/(cm3 s) = 4.1868 x 106 W/m3 1 kcal/(mj h) = 1.163 W/m3

British thermal unit per cubic foot hour 1 Btu/(ftJ h) = 10.3497 W/m3

[caI/(cm3 s)] [kcaI/(m3 h)l

48.3 A similar imperial unit is: [Btu/(ft3 h)]


Table 48. Heat release rate Exact values are printed in bold type.

1 I I caiorie*[cubic centirnetre second cal/(cm3 s)

0.238 846 x 10 -6

1

2.777 78 x 10 -7

2.471 99 x 10 -6

kuocalorie*/cubic metre hour kcai/(m3 h)

0.859 845

3.6 x 106

1

8.899 15

I I I * This refers to the International Table calorie. For other calories see 36.6, 1 W/cmJ = 106 W/m3 = 1 MW/m3.

49. Thermal diff usivity (area/time)

British thermal unit/cubic foot hour BhJ(ft3 h)

9.662 Il x 10 -2

4.045 3 3 ~ 105

0.112 370

i

I

O

The SI unit of thermal diffusivity (which is thermal conductivity divided by heat capacity per unit volume) is the metre squared per second (mys).

Since kinematic viscosity has the same dimensions as thermal diffusivity, for units and conversion factors reference can be made to Section 35 and Table 35.

77


BSI BS*350: PART*L 74 Lb24bbî OLlbL95 9 = BS 350 : Part I : 1974 Commentary

Appendix A

Commentary on imperial and metric systems of measurement and units

A.l Development of units. In the past, units have evolved in a haphazard manner to meet the basic iiieasure- ment requirements of early and often unconnected societies. With improvement in communications and extension of trade it became necessary to standardize the units in use and also to establish the relationship between existing units used to measure the same physical quantities. Often, as this latter process developed, the numerical factors relating one such unit to another were cumbersome and difficult to use in calculations (for example, the mile is 1760 yards and the U K ton is 2240 pounds). Moreover, while one physical quantity might be a simple derivative of another, there was often no correspondingly simple relationship between their respective units, (for example, area and volume are simple derivatives of length, but 1 acre is484ûsquare yards and 1 UK gallon is 0.160 544 cubic feet).

As science and technology developed, many new aiid coinplex units were required. Inevitably these were derived froin tlie available units in common usage and the result was a muddled conglomeration of technical units involving many awkwíird factors which were difficult to renieinber and inconvenient to use. The leariiing of these factors has long becii a necessary part of scieiitific aiid eiigiiieeriiig education.

A.2 Unit systenis and coherence. The various physical quantities used in science and technology are related to one another by certain mathematical or physical laws. For example, area equals length multiplied by length, velocity equals length divided by time, force equals mass niultiplied by acceleration, momentum equals mass multiplied by velocity.

In a coherent system of units, the units used to measure the various physical quantities are consistent with these physical laws. A minimum number of independent physical quaniities are arbitrarily selected and base units are defined for these. Units for all other physical quantities can then be derived in accordance with the physical laws, preserving a unity relationship in terms of the base units. Thus, if unit area results when unit length is multiplied by unit length, the units are coherent with the particular physical law expressing tlie relationship between length and area, and no factors are involved in calculations concerned with this relationship.

With further development of science and technology, certain ' systems ' of units came into use, (for example the foot-pound-second system and the centinietre-gram-second system). While the base units concerned were clearly defined, the total extent of each of these systems and also units for some physical quantities were in certain respects vague. The units comprising these systems were coherent with respect to some of the physical laws, but not to others.

A.3 Imperial systems (in technology). In British technology the most widely used system has been one in which the base units for length, mass and time are the foot, pound and second respectively. But, in this widely-used system there is a non-coherent relationship between the units used for mass, force and acceleration i.e. there is not ' dynamic coherence '. The unit of force used is the pound-force (sometimes described as a ' technical unit of force '), aiid, because this force acting on a mass of one pound produces an acceleration of ' g ' (=32.2 feet/second2 approximately), the factor 32.2 is introduced in an awkward manner into many engineering calculations.

There are two other systems based on imperial units used in some sections of industry which are dynamically Coherent. The first is a variant of the foot-pound-second system which has the poundal as its force unit. The poundal acting on a mass of one pound produces an acceleration of unity (1 foot/second2). The other is the foot-slug-second system in which the mass unit is the slug (=32.2 lb approximately) and the force unit the pound-force. Again, the acceleration produced by the pound-force on the slug is unity.

In the above, only dynamic coherence has been mentioned. While this is of vital importance in mechanics, there are many other important physical quantities aiid laws; further base units had to be introduced and the corresponding units that came about in conjunction with these imperial systems were frequently non- coherent. Furthermore, in dealing with the foot-pound-second, and foot-slug-second systems, there are the practical complications in calculations caused by the awkward relationships between the foot, inch and yard, and the pound and ton. In the measurement sense these units all form part of the imperial system.

A.4 Comparison of Uniteù Kingdom (UK or imperial) and United States systems of measurement. The yard lias the same value in both the UK and US systems and is defined in terms of the SI base unit of length, the metre. Similarly, the pound lias the same value in the UK and US systems and is defined in terms of the SI base unit of mass, the kilogram.

78

8

a

a


BSI BS*350: P A R T * & ~~ 7 4 ~~~ = L b 2 4 b b ï O L L b l S b O m _ _ ~ ~ _ _ -~ -

BS 350 : Part 1 : 1974 Commentary

The UK Weights and Measures Act, 1963, makes these deíìnitions valid for all purposes in the UK. Jn the USA the same definitions are valid for all purposes except for coast and geodetic surveys within the USA, for which the foot previously adopted there will continue temporarily to be used under the name ' US survey foot '.

Most of the subsidiary units of length are identical in both the UK and US systems. There are marked differences between some subsidiary units of mass used in the UK and US systems,

notably in the ' long ' and ' short ' tons and hundredweights. These differences arise from different whole number relationships between units.

There are also marked differences between the subsidiary units of capacity used in the UK and US systems, These differences arise both from some different whole number relationships between units and also from different definifions of capacity in the two systems.

In order to avoid confusion where those differences occur, the units to be distinguished are denoted by the use of prefixes, for example:

UK gallon, symbolized by UKgal US gallon, syiiibolized by USgal

This notation is similar to one adopted by the International Organization for Standardization (ISO). In certain contexts the qualification ' imperial ' or ' imp ' is also used to make it clear that the unit qualified by UK does in fact belong to the imperial system of units. A.5 The metric system of measurement. In Britain, units of length, weight (mass) and so on have been standardized for a long time, but prior to the adoption of the metric system this was not the case in France and in other continental countries. When the metric system was introduced it met two main requirements. The first was the standardization and definition of the important units of measurement, the metre for length and the gram for mass, from which other units then required for general use and for trade were derived. The second was the provision of a convenient and systematic relationship between different-sized units for the same quantity. These were related by powers of ten and a system of prefixes developed to indicate these powers. This gave a flexible means of expression for a wide range of magnitudes, avoiding theneed for very iarge or very small numerical values, and enabled the different-sized units to be memorized and converted with ease. A.6 Metric systems (in science and technology). In technology, as at present and taking all countries into account, probably the most widely used metric system is one in which the base units for length, mass and time are the metre, kilogram and second respectively, but in which there is a non-coherent relationship between the units for mass, force and acceleration. The unit of force used is the kilogram-force (sometimes described as a ' hetric technical unit of force '), and because this force acting on a mass of 1 kilogram produces an acceleration of ' g ' (9.81 m/s2 approximately) the factor 9.81 is introduced in an awkward manner into many engineering calculations. The system is being steadily superseded by the International System (SI), mentioned below.

There are other metric systems still in use in some sectors of industry and science which are dynamically coherent, and from the first two of which the development of the SI can directly be traced. Some are:

Description and abbreviation msss unit force unit

centimetre-gram-second (CGS) gram dyne metre-kilogram-second (MKS) kilogram newton metre-tonne-secottd (MTS) tonne sthène

Scientists were quick to recognize the convenience of the metric approach in the CGS and this system was developed by them to meet their immediate needs, according to their knowledge at the time, and among other things it served in the development of electrostatics and electromagnetism. Although it gained con: siderable usage in industrial technology, many of the associated units were inconveniently sized for this purpose. It was also clear that inore than the three base units provided in the CGS were required in the framework of the metric system to deal adequately with the physical quantities required in science and technology, and that some of the subsidiary wits that had come into use in conjunction with the CGS were not coherent.

These factors led in due course to the evolution of the MKS system, thence to the MKSA, incorporating the independent quantity electric current and the base unit ampere. This system embodied the joule as the derived and coherent unit of energy in ail its forms, and the watt as the unit of power. A.7 The Interuatiouai System of units (SI). This, sometimes described as the ' modern metric system ', is the most recent extension of the metric system, expanding on the MKS to include a total of seven base units

79


B S I B S X 3 5 0 : P A R T * & 74 m Lb24bb9 OLlbL97 2 m 1

BS 350 : Part I : 1974 Commentary

and two suppleincntary units which, in conjunction with derived units, will meet ali known needs for a coherent system of units both in science and technology,

The base and supplementary quantities, and their units (defined in BS 3763) are: Quantity Name of unit Symbol Length metre (Base) m Mass kilogram 1, kg Time second 3, S Electric current ampere $ 9 A Thermodynamic temperature kelvin Y > K Amount of substance mole Y, mol Luminous intensity candela 9 , cd Plane angle radian (Supplementary) rad Solid angle steradian 39 sr

There are, for practical applications or for everyday life, certain other units, some metric and some non- metric, which at present are authorized for use in conjunction with the International System. Such units are listed in categories in BS 3763 : 1970 and their use introduces an element of non-coherence.

The metric prefixes, which now form part of the International System, are shown in detail in 1.1. As is evident from the foregoing description of a coherent system, the use of multiples in the form of a prefix also introduces non-coherence, but in the SI the prefìxed units still retain a simple decimal relationship one with the other. This is an important feature, which is not sacrificed by the fact that the base unit for mass is the kilogram.

80


BSI BSS350: PART*I(’L 7Y m ~~~~ 1624669 - OLlb198 ----- 4 m - ~~

BS 350 : Part 1 : 1974 References

Appendix B References

B.l Detailed conversion tables. Detailed conversion tables for the units marked with an asterisk can be found in Asament/e<

PD 6203.

Length inches to minimetres millimetres to inches fractions of an inch, in sixty-fourths, to decimals of

an inch and to inillimetes (Range: O to 1 inch) inches and fractions of an inch to millimetres

(Range: O to 12 inches) inches to centimetres (Range: O to 109 inehes at

intervals of one inch) feet to metres metres to feet feet and inches to metres yards to metres metres to yards miles to kilometres kilometres to miles

Area square inches to square centimetres square centimetres to square inches square feet to square metres square metres to square feet square yards to square metres square metres to square yards acres to hectares hectares to acres square miles to square kilometres square kilometres to square miles

Volume Cubic inches to cubic centimetres Cubic centimetres to cubic inches Cubic feet to cubic metres Cubic metres to cubic feet Cubic yards to cubic metres Cubic metres to cubic yards Cubic feet to UK gallons TJ K gallons to cubic feet Cubic feet to litres (1901) Litres (1901) to cubic feet UK gallons to litres (1901) Litres (1901) to UK gallons UK fluid ounces to millilitres (1901) Millilitres (1901) to UK fluid ounces *UK gallons to litres *Litres to UK gallons *UK fluid ounces to millilitres *Millilitres to UK fluid ounces

Mass per unit length pounds per foot to kilograms per metre kilograms per metre to pounds per foot *pounds per inch to kilograms per metre *kilograms per metre to pounds per inch

Mass per unit area *ounces (avoir) per square yard to kilograms per

*kilograms per square metre to ounces (avoir) per square metre

square yard

Density pounds per cubic foot to kilograms per cubic metre kilograms per cubic metre to pounds per cubic foot pounds per UK gallon to grams per millilitre (1901) grams per millilitre (1901 1 to pounds per UK gallon

81

July IYX.3

Second moment of area inches4 to centimetresd centimetres4 to inches4

Angle degrees, minutes and seconds to radians radiacs to degrees, minutes and seconds

Velocity feet per second to miles per hour miles per hour to feet per second feet per second to kilometres per hour kilometres per hour to feet per second miles per hour to metres per second metres per second to miles per hour miles per hour to UK knots UK knots to miles per hour

Mass grains to grams grams to grains ounces (avoir) to grams grams to ounces (avoir) pounds to kilograms kilograms to pounds UK tons to tonnes tonnes to UK tons pounds to UK tons UK tons to pounds


BS 350 : Part I : 1974 References

Force pounds-force to megadynes megadynes to pounds-force *kilograms-force to newtons "newtons to kilograms-force *pounds-force to newtons "newtons to pounds-force *UK tons-force to kilonewtons *kilonewtons to UK tons-force

Pressure, stress pounds-force per square inch to kilograms-force

kilo4rams-force per square centimetre to pounds-

pounds-force per square foot to kilograms-force

kilograms-force per square metre to pounds-force

UK tons-force per square inch to kilograms-farce

kilograms-force per square milliinetre to UK tons-

UK tons-force per square foot to tonnes-force per

tonnes-force per square metre to U K tons-force per

pounds-force per square inch to millimetres of

millimetres of mercury to pounds-force per square

millimetres of mercury to millibars miliibars to inilliinetres of mercury feet of water to pounds-force per square inch pounds-force per square inch to feet of water *UK tons-force per square inch to meganewtons

*meganewtons per square metre to UK tons-force

*pounds-force per square inch to kilonewtons per

*kilonewtons per square metre to pounds-force per

*pounds-force per square foot to newtons per

"newtons per square metre to pounds-force per

"inches of mercury to kilonewtons per square metre *kilonewtons per square metre to inches of mercury *feet of water to kilonewtons per square metre *kilonewtons per square metre to feet of water *inches of water to kilonewtons per square metre *kilonewtons per square metre to inches of water

per square centimetre

force per square inch

per square metre

per square foot

per square millimetre

force per square inch

square metre

square foot

mercury

inch

per square metre

per square inch

square metre

square inch

square metre

square foot

BSI B W 3 5 0 : PART*L 74 m Lb24bb9 O L L b L 9 9 b m

82

Work, energy foot pounds-force to joules joules to foot pounds-force foot pounds-force to kilogram-force metres kilogram-force metres to foot pouiids-force *kilowatt hours to megajoules "megajoules to kilowatt hours

Power horsepower to kilowatts kilowatts to horsepower

Temperature Conversion of temperatures from degrees Fahren-

heit to degrees Celsius, and vice versa

Quantity of heat British thermal units to kilojoules kilojoules to British thermal units calories to joules joules to calories British thermal units to kilocalories kilocalories to British thermal units

Calorificvalue (mass basis) Btujlb to kcal/kg kcal/kg to Btu/lb *Btu!lb to kJ/kg *kJ!kg to Btu/lb

Calorific value (volume basis) Btu/ft3 to kcal/m3 kcal/m3 to Btu/ft3 *Btu/ft3 to kJ/m3 *kJ/rn3 to Btu/ft3 now called heat capacity (volume basis) in this standard. See also the note on page 83 which applies to many of the following units.

Specific heat (volume basis) Btu/ftJ degF to kcal/m3 degC kcalIm3 degC to Btu/ft3 degF *Btu/ft3 deg F to kJ/m3 degC

. *kJ/m3 deg C to Btu/ft3 degF

Intensity of heat flow rate Btu/ft2 h to W/m2 Wjm2 to Btu/ft2 h kcal/m* h to W/m2 W/m2 to kcal/m2 h Btu/ft2 h to kcal/m2 h kcalfmz h to Btu/ft2 h


BSI BS*350: P A R T * L 7i.1 Lb2qbb9 OLL6200 9 - - ~ --_ -~ ~ ~ _ _ - - ~ ~~

BS 350 : Part I : 1974 References

General information Thermal conductance Thermal conductivity Btu/ft2 li degF to kcal/m2 h degC kcal/m2 h degC to Btu/ft2 h degF *Btu/ft2 h degF to W/m2 degC *W/m2 degC to Btu/ft2 h degF

Btu/ft h degF to W/m degC W/m degC to Btu/ft h degF kcal/m h degC to W/m degC Wlm degC to kcal/m h degC Btu/ft h degF to kcal/m h degC kcal/m h degC to Btu/ft h degF Btu/in/ft2 h degF to kcal/m h degC kcal/m h degC to Btu in/ft2 h degF

NOTE. In this standard degC has been replaced by K and de@ by OF. (See section 38 and, in particular, 38.5).

B2. General information

Useful general information is contained in the following publications. A i urnciiûcd Je11 I W BS 1957

BS 3763 BS 5555 BS 5775

Presentation of numerical values (fineness ofexpression; rounding ofnumbers) The International System ofuni ts (SI) Specification forSI units and recommendations for the use of their multipIesand of certain other units Specification for quantities, units and symbols Part O. General principles Part 1- Space and t ime Part 2. Periodic and related phenomena Part 3. Mechanics Part 4. Heat Part 5. Electricity and magnetism Part 6. Light and related electromagnetic radiations Part 7. Acoustics Part 8. Physicat chemistry and molecular physics Part 9. Atomicand nuclear physics Part IO. Nuclear reactions and ionizing radiations Part 1 I . Mathematical signs and symbols for use id the physical sciences and technology Part 1 2. Dimensionless parameters Part 13. Solid state physics

PD 5686 The useofSI units SI - The International System of Units. HMSO (4th edition 1982) Changing to the metric system. Conversion factors, symbols and definitions. HMSO (5th edition 1979)

63. Some other British Standards containing conversion information British Standard Title BS 718 Density hydrometers and spec& gravity hydrometers BS 860 Tables for comparison of hardness scales BS 874 Methods of determining thermal properties, with definitions of thermal insulating terms BS 947 Universal system for designating linear density of textiles (Tex system) BS 1797 Tables for use in the calibration of volumetric glassware BS 2520 Barometer conventions and tables BS 2856 Precise conversion of inch and metric sizes on engineering drawings

83


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BS 350 : Part 1 : 1974 General information

Alphabetical list of symbolsfor units and prefixes

Symbols and abbreviations for units, and symbols for prefixes, to which any reference has beeii made i i i

this standard, are listed below together with their textual references. Most but not ail of these are internationally recognized.

Greek letters and some special signs are shown at the end. This list is not extended to include combinations of units, or conibinatioiis of prefixes and units, except

for a few examples, Many further examples of such combinations are to be found throughout the text and in the general index, pages 88 to 100.

Symbol or abbreviation

A A a a a at ata atm atü AU bar bbl bbl (dry) Btu Btumean

bu BtU60/ 61

C

C "C

Cal CabT a l i h

d l 5 cd ch C.H.U cl cm CP cSt ctl ' cumec ) ' cusec ' cv cwt d d da deg dm dr dry qt dyn erg

Name of unit or prefix, where appropriate

ampere angström are atto (preiìx) year technical atmosphere technical atmosphere (absolute, German) standard atmosphere technical atmosphere (gauge, German) astronomical unit bar barrel (US, for petroleum) dry barrel (US) British thermal unit mean British thermal unit 60 "F British thermal unit bushel (US) centi (prefix) cycle degree Celsius calorie International Table calorie thermochemical calorie 15 "C calorie candela cheval vapeur (metric horsepower) (French) Centigrade heat unit centilitre centi metre centipoise centistokes cental cubic metre per second cubic foot per second cheval vapeur (metric horsepower, French) hundredweight day deci (prefìx) deca (prefix) (to indicate temperature interval) decimetre dram (avoirdupois) dry quart (US) dyne erg

84

Textual reference

A.7 2.3 3.3 1.1 9, note 2 32.6 32.7 32.6 32.7 2.3 32.2 4.6.3 4.6.4 36.6 36.6 36.6 4.6.2, 4.6.4 1.1 12.1 38.2 36.6 36.6 36.6 36.6 A.7 37, footnote 36.6 4.3 2.2 34.2 35.2 14.5 23, footnote 23, footnote 37, footnote 14.5 9.3 1.1 1.1 38.5 2.2 14.5 4.6.4 28.2 36.2

O

e

e


BS 350 : Part 1 : 1974 General information

Spibol or abbreviation Name of unit or jweiìx, w b m a m t e Textual reference

"F f fi dr fl dr fl oz Fm ft ftH2O G g L?

6"

Gal E

gal gi gon gr h h ha hbar hl hP hP h Hz in inHg inH20 J K k kg kgf kip km kn kP ' k.s.i ' kW kW h 1 Ib Ibf liq dr liq oz liq Pt

qt 1.y. M m m mb

mil' 'mil' ' mil '

degree Fahrenheit femto (prefix) fluid drachm fluid dram (US) fluid ounce Festmeter (German) foot conventional foot of water g i s (prefix) gram acceleration due to gravity standard acceleration due to gravity grade galileo (or gal) gallon gill (US) gon (or grade) grain hecto (prefix) hour hectare hectobar hectolitre horsepower horsepower hour hertz . inch conventional inch of mercury conventional inch of water jouie kelvin kilo (preñx) kilogram kilogram-force loo0 pounds-force (US) kilometre knot (international) kilopond (kilogram-force, German) kips per square inch (US) kilowatt kilowatt hour litre pound pound-force liquid dram (US) liquid ounce (US) liquid pint (US) liquid quart (US) light year mega (prefix) metre milli (prefix) müübar (of area) (of angle) (of length)

38.3 1.1 4.6.1 4.6.3 4.6.1 4.4 2.5 32.5 1.1 14.2 13.4 13.4 7.3 13.2 4.6.1 4.6.3 7.3 14.5 1.1 9.3 3.3 33 4.3 37.3 36.5 12.1 2.5 32.5 32.5 36.1 38.1 1.1 14.1 28.2 28.3 2.2 10.5 28.2 32.4 37.1 36.3 4.3 14.4 28.3 4.6.3, footnote 4.6.3, footnote 4.6.3 4.6.3 2.3 1.1 2.1 1.1 32.2, footnote 3.5, and note 2 7, note 2 . 2.6, and note 8

85


BS 350 : Part I : 1974 General information


'mil, Mg mg mGal d 2 0 min min ml mm -Hg mmH20 mol ms N n n mile ns

oz ap oz apoth OZf

oz t oz tr P P P Pa P C

oz

Pdl Pk P1 PS ' p.s.i ' ' p.s.i.a ' p.s.i.g ' Pt PZ 4 qr qt "R r rad rev ' reyn Rm

sh cwt sn st St st T t th

S

Name of unit or prefix, where appropriate

(of volume) megagram milligram milligal conventional metre of water minute (of time) minim millilitre millimetre conventional millimetre of mercury conventional millimetre of water mole millisecond newton nano (prefix) international nautical mile nanosecond ounce apothecaries' ounce (US) apothecaries' ounce (UK) ounce-force ounce troy (US) ounce troy (UK) pond (gram-force, German) poise pico (prefix) pascal parsec poundal peck (US) poiseuille (French) Pferdestärke (metric horsepower, German) pounds-force per square inch pounds-force per square inch (absolute) pounds-force per square inch (gauge) pint pièze (French) quintal quarter quart degree Rankine revolution radian revolution (viscosity unit) Raummeter (German) second (of time) short hundredweight (US) sthène (French) steradian stokes stère (French) tera (preñx) tonne thermie (French)

86

Textual reference

4.4 14.2 14.2 13.2 32.5 9.3 4.6 4.3 2.2 32.5 32.5 A. 7 9, note 1 28.1 1.1 2.3 9, note I 14.5 14.5 14.5 28.3 14.5 14.5 see 28.2 34.2 1.1 32.1 2.3 28.3 4.6.3 34.1 37, footnote 32.4 32.7 32.7 4.6.1 32.2 14.3 14.5 4.6.1 38.4 11.2 7.1 11.2 34.3, footnote 4.4 9.1 14.5 28.2 8.1 35.2 4.4 1.1 14.2 36.6



tonf

UKgal UKpt UKqt USgal w Yd

U

>

I

I I

Y P ' 11 ' ' P ' Pig pin 1.11 Cim 11s L

BS 350 : Part I : 1974 General information

Name of unit or prefix, where appropriate Textual reference ton-force atomic mass unit gallon (UK) pint (UK) quart (UK) gaiion (US) watt yard degree (of angle) minute (of angle) second (of angie) degree (temperature) ' gamma ' (microgram) micro (prefix) (micron of mercury) micron microgram micro-inch microlit re rnicrometre (or micron) microsecond (right angle)

28.3 14.3 4.6.1 4.6.1 4.6.1 4.6.3 37.1 2.4 7.2 7.2 7.2 38.2 to 38.5 14, note i 1.1 32.5 2.2 14.2 2.6 4.3 2.2 9, note 1 7.1

87


BSI BS*350: P A R T # l 74 B I l b24bb9 O l l b 2 0 5 B

BS 350 : Part I : 1974 General index

General index

The names of the quantities, subjects, units and preíìxes to which reference has been made in this standard are listed below with their references. Against units or prefixes the corresponding symbol is also indicated.

Symbol Textual reference Table reference Term and important notes

absolute (pressure) acceleration acceleration, standard acre acre per pound ampere angle, plane angle, right angle, solid åHgström angular momentum angular velocity apothecaries' units are area area, first moment of area, second moment of area per unit capacity area per unit mass assay ton (UK) assay ton (US) astronomical unit atmosphere, standard atmosphere, technical atmosphere, technical (absolute, German) atmosphere, technical (gauge, German) atomic mass unit atto avoirdupois units

g"

acre/lb A

L

A

a

AU atm at ata ati'

a U

bar barn barrel (beer, UK) barrel (cranberry, US) barrel (wine, UK) barrel (petroleum, US) barrel, dry (US) barye billion British thermal unit British thermal unit, International Table British thermal unit, mean British thermal unit, 60 O F

British thermal unit (used by Gas Industry) British thermal unit inch per square

foot hour degree Fahrenheit British thermal unit per cubic foot British thermal unit per cubic foot

British thermal unit per cubic foot hour degree Fahrenheit

bar

bbl bbl (dry) (dynlcm2)

Btu in/(ft2 h OF) Btu/ft3

Btu/(ft3 OF) Btu/(ftJ h)

32.7 13 13.4 3.4 17.3 A.7 7 7.1 8 2.3 27 11 14.5 3.3 3 5 6 18 17 14.6 and note 3 14.6 and note 4 2.3 32.6 32.6 32.7 32,7 14.3 1.1 14.5

32.2 3.3 4.6, note 1 4.6, note 2 4.6, note 1 4.6.3 4.6.4 32.2 1.2 36.6 36.6 36.6 36.6 36.6

46.4 40.3

43.4 48.3

- 13 13 3a 17

7 7

-

---

- 11 - - - 4a, 4c 6 18 17 - - - 326 32a, 326

46, 14c

4Oa, 40b, 40c

43 48

88


ES1 BS*358: P A R T * L 74 W 1624667 81Lb206 T _ _ ~ ~ ~~~~ - ~

~~

BS 350 : Part 1 : 1974 General index

Term Symbol Textual reference Table referem and important notes

British thermal unit per foot hour degree

British thermal unit per hour British thermal unit per pound British thermal unit per pound degree

British thermal unit per square foot hour British thermal unit per square foot hour

bushel (UK) bushel (US) bushel, international corn

Fahrenheit

FahrenhCit

degree Fahrenheit

cable-length calendar year calorie calorie, dietitians calorie, International Table calorie, kilogram- calorie, thermochemical calorie, tonne- calorie, 15 ' calorie per centimetre second kelvin calorie per cubic centimetre second calorie per second calorie per square centimetre second calorie per square centimetre second kelvin calorific value, gases, with differing

reference conditions calorific value, mass basis calorific value, volume basis candela capaciíy carat, metric Celsius, degree cental centi Centigrade Centigrade heat unit centilitre centimetre centinietre cubed centimetre per second squared centimetre second kelvin per calorie centimetre to the fourth centipoise centistokes chain chain, engineers' chain, Gunter's cheval vapeur (metric horsepower, French) coefficient, heat transfer concentration . conductance, thermal conductivity, thermal

o

.

Btu/(ft h OF) Btu/h Btu/ib

Btu/(lb "F) Btul(ft2 h)

Btul(ft2 h OF)

bu

a Cal

call,

calth

d l 5 cal/(cm s K) cal/(cm3 s) cal/s cal/(cm2 s) cal/(cm2 s K)

cd

CM (see 14, note 2) "C ctl C

C.H.U cl cm cm3 cm/s2 cm s K/cal cm4 CP cst

CV, ch

46.4 37.4 39.3

41.4 44.3

45.4 4.6.1 and note 3 4.6.2, 4.6.4 14.6 and note 6

2.6 and note 16 9.4, footnote 36.6 see 36.6 36.6 see 36.6 36.6 see 36.6 36.6 46.3 48.2 37.4 44.2 45.3

40.4 39 40 A.7 4 14.3 38.2 14.5 1.1 see 38.2 36.6 4.3 2.2 5.2 13.2 47, note 6 34.2 35.2 2.5 2.6 2.5, note 5 37, footnote 45 20 45 .

46

46 37 39

41 44

45 4d k, 4d -

- - 36b use 366 36b use 366 36b use 366 366 46 48 37 44 45

4ûb, 40c 39 &, 4ûb, 40c

4q 4b, 4c, 4d 14b 38

la

-

-

- - use 4a, 4b,4c use 2 use 4a, 4c 13 47 6 34 35 2

2 37 45 20 45 46

-

89


BSI BS*350: P A R T * l 94 e l b 2 4 b b î íJlLb207 E W


Term Symbol Textual reference Table reference and important notes

cord corn bushel, international cran cubic centimetre cubic decimetre cubic foot cubic foot per hour cubic foot per pound cubic foot per second cubic foot per UK ton cubic inch cubic inch per pound cubic metre cubic metre per hour cubic metre per kilogram cubic metre per seEond cubic millimetre cubic yard ' cumec ' cusec cycle cycle per second

day deca deci decimetre dei3 degree Celsius degree Fahrenheit degree (of angle) degree per minute degree per second degree Rankine denier density density, linear density, relative diffusivity, thermal drachm (apothecaries', UK) drachm, fluid (UK) dram (apothecaries', US) dram (avoirdupois) dram, fluid (US) dram, liquid (US) dynamic viscosity dyne dyne per centimetre dyne per square centimetre

cm3 dm3 ft3 ft3/h ft3/lb ft3/s fti/UK ton in3 in3/lb m3 m3/h m3/kg m3/s mm3 Yd3

C

CIS

d da d dm deg "C "F

"/min

"R

O

"Is

UK fl dr

dr fl dr liq dr

dYn dynlcm dyn/cm2

em energy energy, specific Engler degree enthalpy, specific

4.6, note 4 14.6 and note 6 4.6, note 5 4.2 4.2 4.5 23.3 21.3 23.3 21.3 4.5 21.3 4.1 23.2 21.1 23.1 4.2 4.5 23.1, footnote 23.3, footnote see 12.1 12.1

9.3 1.1 1.1 2.2 38.5 38.2 38.3 7.2 11.2 11.2 38.4 15.2 19 15 19, footnote 49 14.5 4.6.1 14.5 14.5 4.6,3 4.6, footnote 34 28.2 31.2 32.2

2.6 and note 13 36 39 35.5 39.1

- - - use 4a, 4c 4a, 46 4a, 46 23 21 23 21 4a, 46, 4c 21 4a, 46 23 21 23 4c 4a 23 23 - -

- l a la use 2

38 38 7 11 11 38

19 15

see 35 14b 4c, 41

14b 4d 4d 34 28

-

-

-

-

- -

- 36a, 36b 39

39 -

90


Term Symbol Textual reference Tabk demœ and important notes

entropy, specific ephemeris second erg .

Fahrenheit, degree fathom .

femto Festmeter (German) flow rate, mass flow rate, volume flux density, heat foot foot, board foot, US survey foot cubed foot hour degree Fahrenheit per British

thermal unit foot of water foot per minute foot per second foot per second squared foot poundal foot pound-force foot pound-force per pound foot pound-force per pound degree

foot pound-force per second foot squared per hour foot squared per second foot to the fourth force force per unit length frequency frigorie furlong

Fahrenheit

gal galileo gallon (UK) gallon (UK) per hour gallon (UK) per mile gallon (UK) per minute gallon (UK) per pound gallon (UK) per second gallon (US) gallon (US) per mile gamma gauge (pressure) giga gill (VK) gill (US) gon I- grade I grain grain per cubic foot

erg

"F

f Fm

ft

ft3

ft h "F/Btu ftH2O ft/min ft/s ft/s2 f t pdl ft lbf ft lbf/lb

ft Ibf/(lb O F )

ft Ibfls ft2/h ft2/s f t4

Gal Gal UKgal UKgal/h UKgal/mile UKgal/min UKgal/lb UKgal/s USgal USgal/mile Y

G

gi gon l. ' I grm3 gr

91

42 9.2 36.2

38.3 2.6 1.1 4.4 22 23 44 2.5 4.6, note 4 2.6 5.3

- 32.5 10.4 10.4 13.3 36.5 36.5 39.3

41.4 37.3 35.4 35.4 6 28 31 12 36.6 2.5

13.2 13.2 4.6.1 23.3 24 23.3 21.3 23.3 4.6.2, 4.6.3 24 14.2, note I 32.7 1.1 4.6.1 4.6.3

7.3

14.5 20.2

see 41

d

38 2 la use 4, 46 22 23 44 2 - - 4a

47 32c 10 10 13 36a 3óa, 36b 39

41 37 35 35 6 28 - - use 366 2

13 13 4th 4d 23 24a 23 21 23 4b, 4á 24a - - la 4d 4d 7

14b 20


BSI BS8350: PARTaL 74 Lb24bb7 OlLb209 5 I

t


Tenn Symbol Textual reference Table reference and important notes

grain per UK gallon grain per US gallon gram gram centimetre squared gram per cubic centimetre gram per cubic decimetre gram per litre gram per millilitre gram per square metre gravity, specific gravity, standard

hand heat heat capacity (volume basis) heat content (volume basis) heat flow rate, intensity of heat flux density heat release rate heat transfer coefficient hectare hectare per kilogram hecto hectobar hectolitre hertz horsepower horsepower, metric horsepower hour hour hundredweight hundredweight, long (US) hundredweight, short (US)

imperial system, commentary on inch inch cubed inch of mercury, conventional inch of water, conventional inch per second inch squared per hour inch squared per second inch to the fourth inertia, geometrical moment of inertia, moment of intensity of heat flow rate inverse second

iron IPTS - 68

joule joule, absolute joule, in terna tional joule per cubic metre joule per cubic metre degree Celsius

ha ha/kg h hbar hl Hz hP see 37.2, footnote hP h h cwt

sh cwt

in in3 inHg inHz0 in/s in2lh in*/s in4

S -1

J J

J/m3 J/(mJ OC)

92

20.2 '

20.2 14.2 25.2 19.2 20.1 20.1 19.2 16.2 19, footnote 13.4

2.6 and note 14 36, 36.6 43 40 44 44 48 45 3.3 17.2 1.1 33 4.3 12. I 37.3 37.2 36.5 9.3 14.5 14.5 14.5

Appendix A 2.5 5.3 32.5 32.5 10.4 35.4 35.4 6 6 25 44 12.1, 12.2 38.6 2.6, note 10

36.1 36.1 36.1 40.1 43.2

20 20 146 25 19 20 20 19 16

13 -

-- 366 43 40n, 406, 40c 44 44

45 3a 17 la 32a see 4a, 4b

37 37 36a, 366

14c

14c

48

-

-

-

- 2 4a, 4c 326, 32c 32c 10 35 35 6 6 25 44 - - - 36a, 366 36a, 366

OU, 40b, 40c 43

-


Term


Table reference Symbol Textual reference and important notes

joule per cubic metre kelvin joule per kilogram joule per kilogram degree Celsius joule per kilogram kelvin

kelvin kilo kilocalorie per cubic metre kilocalorie per cubic metre hour kilocalorie per cubic metre kelvin kilocalorie per hour kilocalorie per kilogram kilocalorie per kilogram kelvin kilocalorie per metre hour kelvin kilocalorie per square metre hour kilocalorie per square metre hour kelvin kilogram kilogram-force kilogram-force metre (energy) kilogram-force metre (torque) kilogram-force metre per kilogram

e

kilogram-force metre per kilogram kelvin kilogram-force metre per second kilogram-force per square centimetre kilogram-force per square metre kilogram-force per square milíimetre kilogram-force second per square metre kilogram metre squared kilogram millimetre squared kilogram per cubic metre (density) kilogram per cubic metre (concentration) kilogram per hectare kilogram per hour kilogram per metre kilogram per metre second kilogram per second kilogram per square metre kilometre kilometre per hour kilometre per litre kilopascal kilopond kilopond met re (energy) kilopond metre (torque) kilopond per square centimetrc kilopond per square metre kilowatt kilowatt hour kinematic viscosity

knot (international) knot (UK)

a

kip (US)

43.1 39.1 41.2 41.1

38.1 1.1 40.2 48.2 43.3 37.4 39.2 41.3 46.3 44.2 45.3 14.1 28.2 36.4 30.2 39.2

41.3 37.2 32.3 32.3 33 34.3 25.1 25.2 19.1 20.1 16.2 22.2 15.1 34.1 22.1 16.1 2.2 10.3 24 32.1 28.2 36.4, footnote 30.2 32.3 see 32.3 37.1 36.3 35 28.3 10.5 10.5

43 39 use 41 41

38 la 40a, 40b, 40c 48 43 37 39 41 46 44 45 14a 28 36u 30 39

41 37 3241,326 32c 32a, footnote 34 25 25 €9 20 16 22 15 see 34 22 16 see2 10 24b see 32a, 32b, 32c 28 36u 30 324 32b 32c use 37 36a, 36b 35 28 10 10



Textual reference Table referemie and important notes

'rem Symbol

39.1 39 2 2 2.3 2.6 and note 12 - 2.6andnotes 11,12 -

15 10

I

latent heat, specific length light year ligne line linear density linear velocity link litre litre (1901) litre atmosphere litre per hour litre per hundred kilometres litre per kilogram litre pei kilometre litre per minute litre per second

mass mass per unit area mass per unit length mass rate of flow mass unit atomic mega megagram megapascal metre metre cubed metre hour kelvin per kilocalorie metre kelvin per watt metre of water metre per second metre per second squared metre squared per hour metre squared per second metre to the fourth metric carat metric horsepower metric system, commentary on micro microgram micro-inch microlitre micrometre micron micron (pressure unit) microsecond ' mil ', circular (of area) ' mi1 ' (of angle) ' mil ' (of length) ' mil ' (of volume) mile

1.y.

I

U

M Mg MPa m m3 m h K/kcal m K/W mH 2 0

m/s m/s2 m2/h m2/s m4 (see 14.3, note 2) (see 37.2, footnote)

mil mil

mile

15 10 2.6 4.3 4.3 36.4 23.2 24 21.2 24 23.2 23.2

14 16 15 22 14.3 1.1 14.2 32.1 2, I 5.1

47 32.5 10.1 13.1 35.3 35,49 6.1 14.3 37.2 Appendix A 1.1 14.2 2.6 4.3 2.2 2.2 32.5 9, note I 3.5 and note 2 7, note 2 2.6 and note 8 4.4 2.5

-

- 4a, 4b, 4c 4a,4b, 4c 36a 23 Fig. I 21 24a 23 23

I&, 146, 14r 16 15 22

ln 14c 32a 2 4a 47 47 see 32a 10 13 35 35 6 14b 37

ia use 14h use 2 use 4c use 2 use 2 use 32c

36

2 4c 2

-

-

-

-


Terni Textnal reference Table reference and important nofes

Symbol

mile, international nautical mile, statute mile, telegraph nautical mile, UK nautical mile per gallon (UK) mile per gallon (US) mire per hour milli millibar milligal milligram milligram per square centimetre milligram per square miliimetre millilitre millimetre millimetre cubed millimetre of mercury, conventional millimetre of water, conventional millimetre to the fourth million mi 11 is eco n d minim (UK) minim (US) minute (of angle) minute (of time) modulus of section mole moment, first, of area moment, geometrical, of inertia moment of force moment of inertia momentum, angular momentum (linear) month

nano nanosecond nautical mile (international) newton newton metre newton per metre newton per square metre newton per square millimetre newton second per square metre number

ounce (apothecaries' UK) ounce (apothecaries' US) ounce (avoirdupois) ounce, fluid (UK) ounce, fluid (US) ounce, liquid (US) ounce-force ounce-force inch ounce inch squared

mGal mg mg/cm2 mg/mm2 ml

mm3 m H g inmH2O mm4

ms UKmin

mm

min

mol

n ns n mile N N m

N/m2 N/mm2 N s/m2

N/m

oz apoth oz ap

um oz usfi oz liq oz OZ€

ozf in oz in2

OZ

95

13.2 14.2 16.2 16.2 4.3 2.2 5.2 32.5 32.5 6 1.2 9, note 1 4.6.1 4.6.3 7.2 9.3 5 A.7 5 6 30 25 27 26 9.4

1.1 .

9, note 1 2.3 28.1 30.1, 36.1 31.1 32.1 33 34.1 1

14.5 14.5 14.5 4.6.1 4.6.3 4.6.3, footnote 28.3 30.3 25.3

n mile 2.3 mile 2.5 and note 6

2.6 2.6 and note 16

mile/UKgal 24 mile/USgal 24 milelh 10.4 m 1.1 mbar (mb) 32.2 and footnote

2 2

2 24b and Fig. 1 246 and Fig. 1 10 la 32b, 32c 13 use 146 16 16 4c use 2 use 4a 32c 32c, footnote 6 lb

4c, 4d

-

-

4d 7

4a

4a 6 30 25

I

-

- - -

la

2 28 30

3241, 324 32c 32a Use 34 la, l b

14b 14b 14b 4c, 4d 4c, 4d 4c, 4d 28 30 25

-

-


BSI BS8350: PART>i(L 7 4 W 3b24bbî OLLb2L3-7 e_- BS 350 : Part 1 : 1974 General index

Term Symbol Textual reference Table reference and important notea

ounce per square foot ounce per square yard ounce per UK gallon ounce per US gallon ounce troy (UK) ounce troy (US)

I parsec pascal pascal second

peck (US) perch Petrograd standard Pferdéstärke (metric horsepower, German) pico pièze pint (UK) pint, dry (US) pint, liquid (US) plane angle point poise poiseuille (French) pole pond (gram-force, German) pound pound foot squared pound-force pound-force foot pound-force hour per square foot pound-force inch pound-force per square foot pound-force per square inch

peck (UK)

pound-force second per square inch gound-force second per square foot pound inch squared pound per acre pound per cubic foot pound per cubic inch pound per foot pound per foot hour pound per foot second pound per (UK) galion pound per (US) ‘gallon pound per hour pound per inch pound per mile pound per second pound per thousand square feet pound per yard pound troy (US) poundal poundal foot

oz/ft2 oz/yd2 oz/UKgal oz/USgal oz tr oz t

PC Pa Pa s

Pk

PS P P= UKpt

liq pt

P P1

P Ib Ib ft2 Ibf Ibf ft lbf h/ft2 lbf in lbf/ft2 Ibf/in2 (p.s.i.)

Ibf s/in2 lbf s/ft2 Ib in2 Ib/acre Ib/ftJ lblin3 Ib/ft lb/(ft h) lb/(ft s) lb/UKgal IbJUSgal lb/h lb/in Ib/mile Ibis lb/loOO ft2 WYd

Pdl pdl ft

16.3 16.3 20.2 20.2 14.5 14.5

2.3 32.1, 33 34.1 4.6.1 4.6.4 2.6 and note 15 4.6, note 4 37, footnote 1.1 32.2 4.6.1 4.6.4 4.6.3 7 2.6 and note 9 34.2 34.1 2.6 and note 15 see 28.2 14.4 25.3 28.3 30.3 34.3 30.3 32.4 32.4 33 34.3 34.3 25.3 16.3 19.3 19.3 15.3 34.3 34.3 19.3 19.3 22.3 15.3 15.3 22.3 16.3 15.3 14.5 28.3 30.3

16 16 20 20 146 146

- 32a, 32b. 32c 34 4d 4d - - 37 la - 4b, 4d % 4d 4b, 4d 7

- l k , 14c 25 28 30 34 30 32c 324 32b 32a, 326

34 25 16 19 19 15 see 34 34 19 19 22 15 15 22 16 15

28 30

-

96


Symbol


Texlual referem Table reference and important notes

poundal per square foot poùndal second per square foot pounds-force per square inch (absolute) pounds-force per square inch (gauge) power pressure

quadrillion quart (UK) quart, dry (US) quart, liquid (US) quarter quintal

radian radian per minute radian per second Rankine, degree Raummeter (German) Redwood number refrigeration, ton of relative density release rate, heat resistivity, thermal revolution per minute

(angular velocity) revolution per minute

(rotational frequency2 revolution per second

(angular velocity) revolution per second

(rotational frequency) ' reyn ' right angle rod rood rotation, speed of rotational speed rotational velocity

Saybolt scale Scale, International Practical

scruple (apothecaries') second (of angle) second (of time) second, ephemeris second, inverse section, modulus of short hundredweight short ton slug slug hour per foot second squared

Temperature, of 1968

pdllft2 pdl s/ft2 p.s.i.a p.s.i.g

UKqt

Iiq qt qr 9

dry qt

rad radtmin rad/s "R Rm

rev/inin r/min rev/min rlmin rev/s rls revls rls

L

IPTS - 68 I I

S

S -1

sh cwt sh ton

slug h/(ft 52)

97

32.4 34.3 32.7 32.7 37 32

1.2 4.6.1 4.6.4 4.63 14.5 14.3

7.1 11.2 11.1 38.4 4.4 35.5 37.4 19, footnote 48 47

11.2

12.3

11.2

12.2 34.3, footnote 7.1 2.6, note 15 3.4, note 1 11, footnote il, footnote li, footnote

35.5

38.6 14.5 7.2 9.1 9.2 12.1, 12.2 5 14.5 14.5 14.6 and note 5 see 34.3

32u 34 - - 37 32a, 326,32c

lb 4d 4d 4d - -

7 11 11 38c use 4a, 4b - .- _- 48 47

11

- 11

- - 7

3a -

- - -

-

- _ -_ 7 - - L

4a 14c 14c 14a Use 34


B S I BS*350: P A R T * l 74 I l b 2 4 b b î OJiLb2L5 O ~


Term Symbol Texhial reference Table reference and important notes

slug per foot second solid angle specific energy specific entropy specific gravity speciñc heat speciñc heat, volume basis

specific heat capacity specific latent heat specific surface specific volume speed speed, rotational square centimetre square centimetre per milligram square decimetre square foot square foot hour degree Fahrenheit

square foot per gallon square foot per ounce square foot (thousand) per pound square inch square kilometre square metre square metre per gram square metre per kilogram square metre per litre square mile square mile per ton square millimetre square millimetre per milligram square yard square yard per gallon square yard per ounce standard, (Petrograd) standard atmosphere standard gravity steradian stère (French) sthène (French) stokes stone stress surface, specific

per British thermal unit inch

technical atmosphere technical atmosphere, absolute, German temperature temperature, thermodynamic temperature difference temperature interval tera tex

slug/(ft s)

CIllZ

cm2/mg dm2 ft2

ft2 h 'F/(Btu in) ft2/gal ft2/oz 1000 ft2/lb in2 km2 m2 m2/g m 2 / k m2/l mile2 mileZ/ton mm2 mm2/mg Yd2 yd2/ga1 yd2/oz

atm gn sr st sn St

at ata

T

34.3 8 39 42 19, footnote 41, footnote 43 and footnotes

41 39.1 17 21 10 11, footnote 3.2 17.2 3.2 3.4

to 41

- 18 17.3 17.3 3.4 3.2 3.1 17.2 17.1 18 3.4 17.3 3.2 17.2 3.4 18 17.3 4.6, note 4 32.6 13.4 8 4.4 28.2 35.2 14.5 33 17

32.6 32.7 38 see 38 38 38 1.1 15.2

34

39 see 41

-

- -

43 41 39 17 21 10

use 30 use 17 use 3a 3a

47 18 17 17 3a, 3b use 3a 3a use 17 17 18 3a 17 36,3a '1 7 3a 18 17

326 13

use 4a, 46 use 28 use 35

32a, 32b, 32c 17

32a, 326

38

-

-

-

-

-

- - - l a -

98


B S I BS*350: PARTxL 74 D Lb24669 O L L b 2 L b 2 ~~~~~ __ ~ ~~~

~


Term ssmbol Textual reference Table reference and important notes

therm therm per gallon .

thermal conductance thermal conductivity thermal diffusivity thermal resistivity thermie thermie per litre thermodynamic temperature ' thou ' time ton ton, assay (U#) ton, assay (US) ton, gross (US) ton, long (US) ton, short (US) ton-force ton-force (US) ton-force foot ton-force per square fûoi ton-force per square inch

therm/UKgal

th th/litre

thou

ton

ah ton tonf ustonf tonf ft

tonf/in* tonf/ft2

ton mile ton mile per gallon ton of refrigeration ton per cubic yard ton per hour ton per mile ton per square mile ton per thousand yards toniie tonne-calorie tonne kilometre tonne kilometre per litre torque torr traffic factors trillion tropical year troy units

unit, atomic mass

' vacuum ' values velocity, angular velocity, linear velocity, rotational viscosity, dynamic viscosity, kinematic volume, and capacity volume, specific volume rate of flow Vollwinkel (German)

UKton d e UKton milejUKga1

tonlyd3 ton/h tonlmile ton/mile* ton/lûûû yd L

t km t km/l

36.6 40.3 45 46 49 47 36.6 40.2 see 38 2.5, note 7 9 14.5 14.6 and note 3 14.6 and note 4 14.5 14.5 14.5 25.3 28.3 30.3 32.4 32.4 33 24 24 37.4 19.3 22.3 15.3 16.3 15.3 14.2 see 36.6 24 24 30 32.5 24 1.2 9.4, footnote 14.5

- 40a 45 46 see 35 47 use 36b 4oa

use 2

14c

-

-

- -

- 14c 28 use 28 30 32a 3% 32a under 246 under 246

19 22 15 16 15 1412 use 36b under 24b under 246 30 32b 244 246 and Fig. 1 Ib

-

-

14.3

32.7 11 10 11, footnote 34 35 4 21 23 7, note 3

- 11 10

34 35 4a, 4b, 4c, 4d 21 23

-

-

99



watt watt per cubic metre watt per metre degree Celsius watt per metre kelvin watt per square inch watt per square metre watt per square metre degree Celsius watt per square metre kelvin week weight

work

Term Symbol Tertiralrefermce Table reference andimportantnotea

W 37.1 37 W/m3 48.1 48

46.2 46 46

Wl(m "Cl W/(m K) 46.1 W/in2 44.3 44 W/m2 44.1 44 W/(m2 OC) 45.2 45 W l W K) 45.1 45

9.4 29 14a, 146, 14c

36 36a, 366

- 28

yard year year, calendar year, light year, tropical

Yd a a ley. a

2.4 9.4 9.4, footnote 2.3 9.4, footnote

1 O0


BSI publications referred to in this standard This standard makes reference to the following British standards:

BS 718 Density hydrometers and specific gravity hydrometers RS 860 Tables for comparison of hardness scales RS 874 Methods of determining thermal properties, with definitions of thermal insulating terms RS 947 Universal system for designating linear density of textiles (Tex System) BS 1797 Tables for lise in the calibration of volumetric glassware ß S 1957 Presentation of numerical values (fineness of expression; rounding of numbers) BS 7570 Barometer conventions and tables BS 2856 Precise conversion of inch and metric sizes on engineering drawings RS 3763 The International System of iinits (SI) PI) 5686 The use of SI iinits

O


BS 350 : Part 1 : 1974

Amd. No.

41 53

~

CONFIRMED OCTOBER 1983

- Date of issue Text affected

July 1983 -

Incorporated in this standard

Amendments issued since publication cr3 cn O ..

l I A - ..

British Standards Institution - 2 Park Street London WIA 2BS - Telephone 01-629 9000 a Telex 266933 a -

8604-8- 1 k- B


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BS350 Conversion Factors and Tables

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